Substrate processing method, substrate processing apparatus and pre-drying processing liquid

ABSTRACT

A pre-drying processing liquid containing a sublimable substance that changes to gas without passing through to a liquid and a solvent in which the sublimable substance dissolves is supplied to a front surface of a substrate on which a pattern has been formed. Thereafter, the solvent is evaporated from the pre-drying processing liquid on the front surface of the substrate to thereby form a solidified body containing the sublimable substance on the front surface of the substrate. Thereafter, the solidified body is sublimated and thereby removed from the front surface of the substrate. A value acquired by multiplying a ratio of the thickness of the solidified body to the height of the pattern by 100 is greater than 76 and less than 219.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2018-119092 filed on Jun. 22, 2018 and Japanese PatentApplication No. 2019-050214 filed on Mar. 18, 2019. The entire contentsof these applications are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a substrate processing method and asubstrate processing apparatus that process a substrate, and to apre-drying processing liquid to be supplied to a front surface of asubstrate before drying the front surface of the substrate. Examples ofsubstrates to be processed include a semiconductor wafer, a substratefor a flat panel display (FPD) such as a liquid crystal display and anorganic electroluminescence (organic EL) display, a substrate for anoptical disc, a substrate for a magnetic disk, a substrate for amagneto-optical disc, a substrate for a photomask, a ceramic substrate,a substrate for a solar cell, and the like.

2. Description of Related Art

In a manufacturing process for semiconductor devices or liquid crystaldisplays, a required process is conducted to substrates such assemiconductor wafers or glass substrates for liquid crystal displays.Such process may include supplying a substrate with a processing liquidsuch as a chemical liquid or a rinse liquid. After the processing liquidis supplied, the processing liquid is removed from the substrate to drythe substrate. In a single substrate processing-type substrateprocessing apparatus that processes substrates one by one, a spin dry isconducted to dry the substrate by rotating the substrate at high speedsand removing a liquid adhering to the substrate.

In a case where a pattern is formed on a front surface of the substrate,when the substrate is being dried, a force due to the surface tension ofthe processing liquid adhering to the substrate applies to the pattern,so that the pattern may collapse. As countermeasures against this, aliquid having a lower surface tension such as IPA (isopropyl alcohol) issupplied to the substrate. Alternatively, a hydrophobizing agent issupplied to the substrate in order to bring the contact angle of theliquid to the pattern closer to 90 degrees. However, a collapsing forceto collapse the pattern does not decrease to zero even when using IPA orthe hydrophobizing agent. Thus, these countermeasures may notsufficiently prevent the collapse of the pattern depending on thestrength of the pattern.

Recently, attention is focused on sublimation drying as a technique toprevent the collapse of the pattern. For example, JP 2012-243869 Adiscloses a substrate processing method and a substrate processingapparatus for sublimation drying. According to the sublimation dryingdisclosed in JP 2012-243869 A, a solution of a sublimable substance issupplied to the upper surface of a substrate, so that the DIW on thesubstrate is replaced with the solution of the sublimable substance.Thereafter, the solvent for the sublimable substance is dried toprecipitate the sublimable substance. This forms a film consisting ofthe solid sublimable substance on the upper surface of the substrate. JP2012-243869 A discloses in paragraph 0028 that “the thickness “t” of thefilm consisting of the sublimable substance is preferably as thin aspossible to the extent that a convex portion 101 of the pattern issufficiently covered.” After the film consisting of the solid sublimablesubstance is formed, the substrate is heated. This causes the sublimablesubstance on the substrate to be sublimated and thus removed from thesubstrate.

SUMMARY OF THE INVENTION

In general, the sublimation drying provides lower pattern collapse ratesas compared with conventional drying methods such as the spin dry toremove a liquid by rotating the substrate at high speeds or the IPAdrying that employs IPA. However, if the pattern is extremely low instrength, even when the sublimation drying is performed, the patterncollapse may not sufficiently be prevented in some cases. According tothe studies by the present inventors, it was found that one of thecauses results from the thickness of a solidified body containing thesublimable substance. In JP 2012-243869 A, described is only “thethickness “t” of the film consisting of the sublimable substance ispreferably as thin as possible to the extent that a convex portion 101of the pattern is sufficiently covered” and the thickness of thesublimable substance film is not sufficiently considered.

One object of the present invention is to provide a substrate processingmethod, a substrate processing apparatus, and a pre-drying processingliquid each of which is able to reduce collapse of patterns that mayoccur when the substrate is dried by sublimation drying.

A preferred embodiment of the present invention provides a substrateprocessing method which includes the following steps, a pre-dryingprocessing liquid supplying step of supplying a front surface of asubstrate, on which a pattern has been formed, with a pre-dryingprocessing liquid containing a sublimable substance that changes to gaswithout passing through to a liquid and a solvent in which thesublimable substance dissolves, a solidified body forming step offorming a solidified body containing the sublimable substance on thefront surface of the substrate by evaporating the solvent from thepre-drying processing liquid on the front surface of the substrate, anda sublimating step of removing the solidified body from the frontsurface of the substrate by sublimating the solidified body. A valueacquired by multiplying a ratio of a thickness of the solidified body toa height of the pattern by 100 is greater than 76 and less than 219.

According to the method, the pre-drying processing liquid that containsthe sublimable substance corresponding to a solute and the solvent issupplied to the front surface of the substrate on which a pattern hasbeen formed. Thereafter, the solvent is evaporated from the pre-dryingprocessing liquid. This allows a solidified body containing thesublimable substance to be formed on the front surface of the substrate.Thereafter, the solidified body on the substrate is changed to gaswithout passing through to a liquid. This results in the solidified bodybeing removed from the front surface of the substrate. Therefore, ascompared with a conventional drying method such as the spin dry, thepattern collapse rate can be lowered.

When the solvent is evaporated from the pre-drying processing liquid,the solidified body containing the sublimable substance is formed on thefront surface of the substrate. Defining a value acquired by multiplyinga ratio of the thickness of the solidified body to the height of thepattern by 100 as an embedding rate, the embedding rate at the time ofthe solidified body being formed is greater than 76 and less than 219.If the embedding rate is out of the range, the number of collapsedpatterns increases depending on the strength of the pattern. Conversely,if the embedding rate is within the range, the number of collapsedpatterns can be reduced even if the strength of the pattern is low.Therefore, even if the strength of the pattern is low, the patterncollapse rate can be lowered.

In the preferred embodiment, at least one of the following features maybe added to the substrate processing method.

The sublimable substance contains at least one of camphor andnaphthalene.

The solvent contains at least one of IPA (isopropyl alcohol), acetone,and PGEE (propylene glycol monoethyl ether).

The solvent is IPA, and the mass percent concentration of the sublimablesubstance in the pre-drying processing liquid is greater than 0.62 andless than 2.06.

The solvent is acetone, and the mass percent concentration of thesublimable substance in the pre-drying processing liquid is greater than0.62 and 0.96 or less.

The solvent is PGEE, and the mass percent concentration of thesublimable substance in the pre-drying processing liquid is greater than3.55 and 6.86 or less.

The pre-drying processing liquid supplied to the front surface of thesubstrate in the pre-drying processing liquid supplying step is asolution that contains the following, the sublimable substancecontaining a hydrophobic group, the solvent, and an adsorbent substancethat contains a hydrophobic group and a hydrophilic group and is higherin hydrophilicity than the sublimable substance.

According to the method, the pre-drying processing liquid that containsthe adsorbent substance in addition to the sublimable substance and thesolvent is supplied to the front surface of the substrate on which thepattern has been formed. Thereafter, the solvent is evaporated from thepre-drying processing liquid. This allows the solidified body containingthe sublimable substance to be formed on the front surface of thesubstrate. Thereafter, the solidified body on the substrate is changedto gas without passing through to a liquid. This results in thesolidified body being removed from the front surface of the substrate.Therefore, the pattern collapse rate can be lowered as compared with aconventional drying method such as the spin dry.

The sublimable substance is a substance that contains the hydrophobicgroup in the molecule. The adsorbent substance is a substance thatcontains the hydrophobic group and the hydrophilic group in themolecule. The adsorbent substance is higher in hydrophilicity than thesublimable substance. Even if the surface of the pattern is eitherhydrophilic or hydrophobic, or alternatively, even if the surface of thepattern includes a hydrophilic portion and a hydrophobic portion, theadsorbent substance in the pre-drying processing liquid is adsorbed tothe surface of the pattern.

Specifically, if the surface of the pattern is hydrophilic, thehydrophilic group of the adsorbent substance in the pre-dryingprocessing liquid is adhered to the surface of the pattern, while thehydrophobic group of the sublimable substance in the pre-dryingprocessing liquid is adhered to the hydrophobic group of the adsorbentsubstance. This allows the sublimable substance to be held on thesurface of the pattern through the adsorbent substance. If the surfaceof the pattern is hydrophobic, at least the hydrophobic group of thesublimable substance is adhered to the surface of the pattern.Therefore, whether the surface of the pattern is hydrophilic orhydrophobic, or alternatively, whether the surface of the patternincludes a hydrophilic portion and a hydrophobic portion, the sublimablesubstance is held on the surface of the pattern or in its vicinitybefore the solvent is evaporated.

If the sublimable substance is hydrophilic and the surface of thepattern is hydrophilic, the sublimable substance is attracted to thesurface of the pattern due to electrical attractive force. Meanwhile, ifthe sublimable substance is hydrophobic but the surface of the patternis hydrophilic, such attractive force is weak or never occurs. Thus, thesublimable substance is unlikely to adhere to the surface of thepattern. Furthermore, if the sublimable substance is hydrophobic, thesurface of the pattern is hydrophilic, and patterns have very narrowspacings, it is thought that a sufficient amount of sublimable substancedoes not enter between the patterns. These phenomena also occur when thesublimable substance is hydrophilic and the surface of the pattern ishydrophobic.

If the solvent is evaporated in a state where no sublimable substance isfound on the surface of the pattern or in its vicinity, the solvent incontact with the surface of the pattern may apply a collapsing force tothe pattern, so that the pattern may collapse. If the solvent isevaporated in a state where an insufficient amount of sublimablesubstance is found between patterns, it is also thought that thespacings of the patterns are not filled with the solidified body, sothat the pattern is collapsed. By disposing the sublimable substance onthe surface of the pattern or in its vicinity before the solvent isevaporated, such collapse can be reduced. This makes it possible tolower the pattern collapse rate.

The hydrophilic group may be any one of a hydroxyl group (hydroxyradical, hydroxyl radical), carboxy group (COOH), amino group (NH₂), andcarbonyl group (CO) or alternatively, may be one other than those. Thehydrophobic group may be any one of a hydrocarbon group, alkyl group(C_(n)H_(2n+1)), cycloalkyl group (C_(n)H_(2n+1)), and phenyl group(C₆H₅), or alternatively, may be one other than those.

The adsorbent substance is a substance having sublimability.

According to the method, not only the sublimable substance but also theadsorbent substance has sublimability. The adsorbent substance changesfrom solid to gas without passing through to a liquid at normaltemperature or at normal pressure. If at least a portion of the surfaceof the pattern is hydrophilic, the solvent is evaporated in a statewhere the adsorbent substance in the pre-drying processing liquid isadsorbed to the surface of the pattern. The adsorbent substance changesfrom liquid to solid on the surface of the pattern. This causes thesolidified body containing the adsorbent substance and the sublimablesubstance to be formed. Thereafter, the solid adsorbent substancechanges to gas without passing through to a liquid on the surface of thepattern. Therefore, the collapsing force can be lowered as compared withthe case in which the liquid is vaporized on the surface of the pattern.

The concentration of the adsorbent substance in the pre-dryingprocessing liquid is lower than the concentration of the solvent in thepre-drying processing liquid.

According to the method, the pre-drying processing liquid with theadsorbent substance having a lower concentration is supplied to thefront surface of the substrate. If at least a portion of the surface ofthe pattern is hydrophilic, the hydrophilic group of the adsorbentsubstance is adhered to the surface of the pattern, and themonomolecular film of the adsorbent substance is formed along thesurface of the pattern. If the adsorbent substance has a highconcentration, a plurality of monomolecular films are stacked in layers,and the stacked film of the adsorbent substance is formed along thesurface of the pattern. In this case, the sublimable substance is heldon the surface of the pattern through the stacked film of the adsorbentsubstance. If the stacked film of the adsorbent substance is thick, thesublimable substance that enters between patterns is reduced. Therefore,by lowering the concentration of the adsorbent substance, a moresublimable substance can be entered between the patterns.

If at least a portion of the surface of the pattern is hydrophilic, theconcentration of the adsorbent substance in the pre-drying processingliquid may take on a value that allows the monomolecular film of theadsorbent substance to be formed on the surface of the pattern oralternatively, may take on a value greater than that. In the formercase, the sublimable substance is held on the surface of the patternthrough the monomolecular film of the adsorbent substance. Therefore,even if at least a portion of the surface of the pattern is hydrophilic,the sublimable substance can be disposed in the vicinity of the surfaceof the pattern. Furthermore, since only the thinnest monomolecular filmof the adsorbent substance is present between the sublimable substanceand the pattern, a sufficient amount of the sublimable substance canenter between the patterns.

The sublimable substance is higher in hydrophobicity than the adsorbentsubstance. The solubility of the sublimable substance in oil is higherthan the solubility of the adsorbent substance in oil. In other words,the solubility of the sublimable substance in water is lower than thesolubility of the adsorbent substance in water.

According to the method, the pre-drying processing liquid containing thesublimable substance that is higher in hydrophobicity than the adsorbentsubstance is supplied to the front surface of the substrate. Both thesublimable substance and the adsorbent substance contain the hydrophobicgroup. Thus, if at least a portion of the surface of the pattern ishydrophobic, both the sublimable substance and the adsorbent substancecan be adhered to the surface of the pattern. However, since theaffinity between the sublimable substance and the pattern is higher thanthe affinity between the adsorbent substance and the pattern, a moresublimable substance than an adsorbent substance is adhered to thesurface of the pattern. This allows more sublimable substance to beadhered to the surface of the pattern.

Another preferred embodiment of the present invention provides asubstrate processing apparatus including a pre-drying processing liquidsupplying unit that supplies a front surface of a substrate, on which apattern has been formed, with a pre-drying processing liquid containinga sublimable substance that changes to gas without passing through to aliquid and a solvent in which the sublimable substance dissolves, asolidified body forming unit that forms a solidified body containing thesublimable substance on the front surface of the substrate byevaporating the solvent from the pre-drying processing liquid on thefront surface of the substrate, and a sublimating unit that removes thesolidified body from the front surface of the substrate by sublimatingthe solidified body. A value acquired by multiplying a ratio of athickness of the solidified body to a height of the pattern by 100 isgreater than 76 and less than 219. The arrangement enables providing thesame effects as those of the substrate processing method describedabove.

Still another preferred embodiment of the present invention provides apre-drying processing liquid that is to be supplied to a front surfaceof a substrate before the front surface of the substrate on which apattern has been formed is dried. The pre-drying processing liquidcontains a sublimable substance that changes to gas without passingthrough to a liquid and a solvent in which the sublimable substancedissolves. The pre-drying processing liquid has a concentration of thesublimable substance in which a value acquired by multiplying a ratio ofa thickness of a solidified body to a height of the pattern by 100 isgreater than 76 and less than 219 when the solidified body containingthe sublimable substance on the front surface of the substrate is formedby evaporating the solvent from the pre-drying processing liquid on thefront surface of the substrate. The arrangement enables providing thesame effects as those of the substrate processing method describedabove.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a substrate processing apparatusaccording to a first preferred embodiment of the present invention whenviewed from above.

FIG. 1B is a schematic view of the substrate processing apparatus whenviewed from the side.

FIG. 2 is schematic view showing the inside of a processing unit, whenviewed horizontally, which is provided in the substrate processingapparatus.

FIG. 3 is a schematic view showing a pre-drying processing liquidsupplying unit provided in the substrate processing apparatus.

FIG. 4 is a block diagram showing the hardware of a controller.

FIG. 5 is a process chart for describing an example of substrateprocessing according to the first preferred embodiment.

FIG. 6A is a schematic view showing the state of the substrate when thesubstrate processing shown in FIG. 5 is performed.

FIG. 6B is a schematic view showing the state of the substrate when thesubstrate processing shown in FIG. 5 is performed.

FIG. 6C is a schematic view showing the state of the substrate when thesubstrate processing shown in FIG. 5 is performed.

FIG. 7 is a graph showing an example image in which a solvent isevaporated to thereby reduce the thickness of the liquid film of thepre-drying processing liquid on the substrate.

FIG. 8 is a graph showing an example of the relationship between theinitial concentration of a sublimable substance and the thickness of asolidified body.

FIG. 9 is a table showing an example of embedding rates and patterncollapse rates that were acquired when a plurality of samples, on whichpatterns having similar shapes and strengths had been formed, wereprocessed while the initial concentration of camphor was being altered.

FIG. 10 is a line graph showing the relationship between theconcentration of camphor and the pattern collapse rate in FIG. 9.

FIG. 11 is a line graph showing the relationship between the embeddingrate and the pattern collapse rate in FIG. 9.

FIG. 12A and FIG. 12B are schematic views for describing a possiblemechanism for a phenomenon in which an excessively thicker solidifiedbody causes a higher pattern collapse rate.

FIG. 13A and FIG. 13B are schematic views for describing a possiblemechanism for a phenomenon in which an excessively thinner solidifiedbody causes a higher pattern collapse rate.

FIG. 14 is a table showing an example of pattern collapse rates thatwere acquired when a plurality of samples, on which patterns havingsimilar shapes and strengths had been formed, were processed while theinitial concentration of camphor was being altered.

FIG. 15 is a table showing an example of pattern collapse rates thatwere acquired when a plurality of samples, on which patterns havingsimilar shapes and strengths had been formed, were processed while theinitial concentration of camphor was being altered.

FIG. 16 is a table showing an example of pattern collapse rates thatwere acquired when a plurality of samples, on which patterns havingsimilar shapes and strengths had been formed, were processed while theinitial concentration of camphor was being altered.

FIG. 17 is a line graph showing the relationship between theconcentration of camphor and the pattern collapse rate in FIG. 14.

FIG. 18 is a line graph showing the relationship between theconcentration of camphor and the pattern collapse rate in FIG. 15.

FIG. 19 is a line graph showing the relationship between theconcentration of camphor and the pattern collapse rate in FIG. 16.

FIG. 20 is a graph by overlapping the lines of FIG. 17 to FIG. 19.

FIG. 21 is schematic view showing the inside of a processing unit, whenviewed horizontally, which is provided in a substrate processingapparatus according to a second preferred embodiment.

FIG. 22 is a process chart for describing an example of substrateprocessing according to the second preferred embodiment.

FIG. 23A is a cross-sectional view of a substrate for describing aphenomenon that is expected to occur on the surface of the pattern towhich the pre-drying processing liquid has been supplied.

FIG. 23B is a cross-sectional view of the substrate for describing thesame phenomenon.

FIG. 23C is a cross-sectional view of the substrate for describing thesame phenomenon.

FIG. 23D is a cross-sectional view of the substrate for describing thesame phenomenon.

FIG. 23E is a cross-sectional view of the substrate for describing thesame phenomenon.

FIG. 23F is a cross-sectional view of the substrate for describing thesame phenomenon.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the descriptions below, unless otherwise specified, it is to beunderstood that the atmospheric pressure inside a substrate processingapparatus 1 is kept at atmospheric pressure inside a clean room in whichthe substrate processing apparatus 1 is installed (e.g., one atmosphericpressure or a value in its vicinity).

FIG. 1A is a schematic view of a substrate processing apparatus 1according to a first preferred embodiment of the present invention whenviewed from above. FIG. 1B is a schematic view of the substrateprocessing apparatus 1 when viewed from the side.

As shown in FIG. 1A, the substrate processing apparatus 1 is a singlesubstrate processing-type apparatus which processes disc-shapedsubstrates W such as a semiconductor wafer one by one. The substrateprocessing apparatus 1 includes load ports LP which hold carriers C thathouse one or more substrates W, a plurality of processing units 2 whichprocess the substrates W transferred from the carriers C on the loadports LP with a processing fluid such as a processing liquid or aprocessing gas, transfer robots which transfer the substrates W betweenthe carriers C on the load ports LP and the processing units 2 and acontroller 3 which controls the substrate processing apparatus 1.

The transfer robots include an indexer robot IR which carries thesubstrates W into and out from the carriers C on the load ports LP and acenter robot CR which carries the substrates W into and out from theprocessing units 2. The indexer robot IR transfers the substrates Wbetween the load ports LP and the center robot CR, the center robot CRtransfers the substrates W between the indexer robot IR and theprocessing units 2. The center robot CR includes hands H1 which supportthe substrates W and the indexer robot IR includes hands H2 whichsupport the substrates W.

The plurality of processing units 2 forma plurality of towers TWdisposed around the center robot CR in a plan view. FIG. 1A shows anexample in which four towers TW are formed. The center robot CR is ableto access each of the towers TW. As shown in FIG. 1B, each of the towersTW includes the plurality of (for example, three) processing units 2which are stacked vertically.

FIG. 2 is schematic view showing the inside of a processing unit 2, whenviewed horizontally, which is provided in the substrate processingapparatus 1.

The processing unit 2 is a wet-processing unit 2W which provides theprocessing liquid to the substrate W. The processing unit 2 includes abox-shaped chamber 4 which has an internal space, a spin chuck 10 whichrotates one substrate W around a vertical rotation axis A1 passingthrough the central portion of the substrate W while holding thesubstrate W horizontally within the chamber 4 and a tubular processingcup 21 which surrounds the spin chuck 10 around the rotation axis A1.

The chamber 4 includes a box-shaped partition wall 5 provided with acarry-in/carry-out port 5 b through which the substrate W passes, and ashutter 7 to open and close the carry-in/carry-out port 5 b. An FFU 6(fan filter unit) is disposed on an air outlet 5 a that is provided onthe upper portion of the partition wall 5. The FFU 6 supplies clean air(filtered air) all the time through the air outlet 5 a into the chamber4. A gas inside the chamber 4 is discharged from the chamber 4 throughan exhaust duct 8 that is connected to the bottom portion of theprocessing cup 21. Thus, the downflow of clean air is formed inside thechamber 4 all the time. The flow rate of the discharged gas that isdischarged into the exhaust duct 8 changes depending on the openingdegree of an exhaust valve 9 that is disposed inside the exhaust duct 8.

The spin chuck 10 includes a disc-shaped spin base 12 which is held in ahorizontal posture, a plurality of chuck pins 11 which hold thesubstrate W in the horizontal posture above the spin base 12, a spinshaft 13 which extends downward from the central portion of the spinbase 12 and a spin motor 14 which rotates the spin base 12 and the chuckpins 11 by rotating the spin shaft 13. The spin chuck 10 is not limitedto a clamping type chuck which brings the chuck pins 11 into contactwith the outer circumferential surface of the substrate W, and the spinchuck 10 may be a vacuum-type chuck which sucks the rear surface (lowersurface) of the substrate W that is a non-device formation surface tothe upper surface 12 u of the spin base 12 so as to hold the substrate Whorizontally.

The processing cup 21 includes a plurality of guards 24 to receive aprocessing liquid discharged outwardly from the substrate W, a pluralityof cups 23 to receive the processing liquid guided downwardly by theplurality of guards 24, and a cylindrical outer wall member 22 thatsurrounds the plurality of guards 24 and the plurality of cups 23. FIG.2 shows an example in which four guards 24 and three cups 23 areprovided, and the outermost cup 23 is integrated with the guard 24 thatis the third from the top.

The guard 24 includes a cylindrical portion 25 that surrounds the spinchuck 10, and an annular ceiling portion 26 that extends diagonallyupwardly toward the rotation axis A1 from the upper end portion of thecylindrical portion 25. The plurality of ceiling portions 26 are stackedin the vertical direction, and the plurality of cylindrical portions 25are disposed concentrically. The annular upper end of the ceilingportions 26 corresponds to the upper end 24 u of the guards 24 thatsurround the substrate W and the spin base 12 in plan view. Theplurality of cups 23 are disposed below the plurality of cylindricalportions 25, respectively. The cup 23 defines an annularliquid-receiving groove that receives a processing liquid that is guideddownwardly with the guard 24.

The processing unit 2 includes a guard elevating/lowering unit 27 toindividually elevate and lower the plurality of guards 24. The guardelevating/lowering unit 27 locates the guards 24 at an arbitraryposition from an upper position to a lower position. FIG. 2 shows astate in which two guards 24 are disposed at an upper position, and theremaining two guards 24 are disposed at a lower position. The upperposition is a position in which the upper end 24 u of the guards 24 isdisposed higher than a holding position in which the substrate W held bythe spin chuck 10 is disposed. The lower position is a position in whichthe upper end 24 u of the guards 24 is disposed lower than the holdingposition.

A processing liquid is supplied to the rotating substrate W in a statein which at least one guard 24 is disposed at the upper position. In thestate, when the processing liquid is supplied to the substrate W, theprocessing liquid supplied to the substrate W flies off around thesubstrate W. The flied-off processing liquid collides with the innersurface of the guard 24 horizontally opposing the substrate W, and isthen guided with the cup 23 that is associated with the guard 24. Thisallows the processing liquid discharged from the substrate W to becollected in the processing cup 21.

The processing unit 2 includes a plurality of nozzles to discharge theprocessing liquid to the substrate W held with the spin chuck 10. Theplurality of nozzles include a chemical liquid nozzle 31 to discharge achemical liquid to the upper surface of the substrate W, a rinse liquidnozzle 35 to discharge a rinse liquid to the upper surface of thesubstrate W, a pre-drying processing liquid nozzle 39 to discharge thepre-drying processing liquid to the upper surface of the substrate W,and a replacing liquid nozzle 43 to discharge a replacement liquid tothe upper surface of the substrate W.

The chemical liquid nozzle 31 may be a scan nozzle that is horizontallymovable within the chamber 4 or alternatively, may also be a fixednozzle that is secured to the partition wall 5 of the chamber 4. Thesame applies to the rinse liquid nozzle 35, the pre-drying processingliquid nozzle 39, and the replacing liquid nozzle 43. FIG. 2 shows anexample in which each of the chemical liquid nozzle 31, the rinse liquidnozzle 35, the pre-drying processing liquid nozzle 39, and the replacingliquid nozzle 43 is a scan nozzle, and four nozzle moving unitsassociated with those four nozzles respectively are provided.

The chemical liquid nozzle 31 is connected to a chemical liquid piping32 that guides a chemical liquid to the chemical liquid nozzle 31. Whena chemical liquid valve 33 interposed in the chemical liquid piping 32is opened, the chemical liquid is continuously discharged downwardlyfrom the discharge port of the chemical liquid nozzle 31. The chemicalliquid to be discharged from the chemical liquid nozzle 31 may be aliquid that contains at least one of sulfuric acid, nitric acid,hydrochloric acid, hydrofluoric acid, phosphorus acid, acetic acid,ammonia water, a hydrogen peroxide solution, organic acid (e.g., such ascitric acid or oxalic acid), organic alkaline (e.g., TMAH: tetramethylammonium hydroxide), a surface-active agent, and a corrosion inhibitor,or alternatively, may be a solution other than those.

Although not shown, the chemical liquid valve 33 includes a valve bodyprovided with an internal flow path where the liquid flows and anannular valve seat surrounding the internal flow path, a valve memberwhich is movable with respect to the valve seat and an actuator whichmoves the valve member between a closed position where the valve membercontacts the valve seat and an open position where the valve member isseparated from the valve seat. The same applies to other valves. Theactuator may be a pneumatic actuator or an electric actuator or anactuator other than those. The controller 3 opens and closes thechemical liquid valve 33 by controlling the actuator.

The chemical liquid nozzle 31 is connected to a nozzle moving unit 34that moves the chemical liquid nozzle 31 at least in one of the verticaland horizontal directions. The nozzle moving unit 34 horizontally movesthe chemical liquid nozzle 31 between a processing position, at whichthe chemical liquid discharged from the chemical liquid nozzle 31 issupplied to the upper surface of the substrate W, and a standby positionat which the chemical liquid nozzle 31 is positioned around theprocessing cup 21 in plan view.

The rinse liquid nozzle 35 is connected to a rinse liquid piping 36 thatguides a rinse liquid to the rinse liquid nozzle 35. When a rinse liquidvalve 37 interposed in the rinse liquid piping 36 is opened, the rinseliquid is continuously discharged downwardly from the discharge port ofthe rinse liquid nozzle 35. For example, the rinse liquid dischargedfrom the rinse liquid nozzle 35 is pure water (DIW (Deionized Water)).The rinse liquid may be any one of carbonated water, electrolyzed ionwater, hydrogen water, ozone water, and hydrochloric acid water of adiluted concentration (e.g., approximately 10 to 100 ppm).

The rinse liquid nozzle 35 is connected to a nozzle moving unit 38 thatmoves the rinse liquid nozzle 35 at least in one of the vertical andhorizontal directions. The nozzle moving unit 38 horizontally moves therinse liquid nozzle 35 between the processing position, at which therinse liquid discharged from the rinse liquid nozzle 35 is supplied tothe upper surface of the substrate W, and the standby position at whichthe rinse liquid nozzle 35 is located around the processing cup 21 inplan view.

The pre-drying processing liquid nozzle 39 is connected to a pre-dryingprocessing liquid piping 40 that guides the processing liquid to thepre-drying processing liquid nozzle 39. When a pre-drying processingliquid valve 41 interposed in the pre-drying processing liquid piping 40is opened, the pre-drying processing liquid is continuously dischargeddownwardly from the discharge port of the pre-drying processing liquidnozzle 39. Likewise, the replacing liquid nozzle 43 is connected to areplacing liquid piping 44 that guides a replacement liquid to thereplacing liquid nozzle 43. When a replacing liquid valve 45 interposedin the replacing liquid piping 44 is opened, the replacement liquid iscontinuously discharged downwardly from the discharge port of thereplacing liquid nozzle 43.

The pre-drying processing liquid is a solution that contains asublimable substance corresponding to a solute, and a solvent in whichthe sublimable substance dissolves. The sublimable substance may be asubstance that changes from solid to gas without passing through to aliquid at normal temperature (the same as the room temperature) or atnormal pressure (the pressure inside the substrate processing apparatus1, e.g., at one atmospheric pressure or a value in its vicinity). Thesolvent may be such a substance or other than that. That is, thepre-drying processing liquid may contain two or more types of substancesthat change from solid to gas without passing through to a liquid atnormal temperature or at normal pressure.

For example, the sublimable substance may be any one of alcohol (forexample, 2-methyl-2-propanol (alias: tert-butyl alcohol, t-butylalcohol, tertiary butyl alcohol) or cyclohexanol), a fluorinatedhydrocarbon compound, 1,3,5-trioxane (alias: metaformaldehyde), camphor,naphthalene, iodine, and cyclohexane, or alternatively, may be asubstance other than those.

For example, the solvent may be at least one type selected from thegroup consisting of pure water, IPA, HFE (hydrofluoroether), acetone,PGMEA (propylene glycol monomethyl ether acetate), PGEE (propyleneglycol monoethyl ether, 1-ethoxy-2-propanol), ethylene glycol, andhydrofluorocarbon.

Now, description will be made below for an example in which thesublimable substance is camphor, and the solvent is any one of IPA,acetone, and PGEE. The vapor pressure of IPA is higher than that ofcamphor. Likewise, the vapor pressures of acetone and PGEE are higherthan the vapor pressure of camphor. The vapor pressure of acetone ishigher than that of IPA, and the vapor pressure of IPA is higher thanthat of PGEE. The freezing point of camphor (the freezing point at oneatmospheric pressure; the same applies hereinafter) is 175 to 177° C.Even if the solvent is any one of IPA, acetone, and PGEE, the freezingpoint of camphor is higher than the boiling point of the solvent. Thefreezing point of camphor is higher than that of the pre-dryingprocessing liquid. The freezing point of the pre-drying processingliquid is lower than the room temperature (23° C. or a value in itsvicinity). The substrate processing apparatus 1 is disposed inside aclean room that is maintained at room temperature. Therefore, evenwithout heating the pre-drying processing liquid, the pre-dryingprocessing liquid can be maintained in the form of liquid. The freezingpoint of the pre-drying processing liquid may be equal to or greaterthan room temperature.

As described below, the replacement liquid is supplied to the uppersurface of the substrate W covered with the liquid film of the rinseliquid, and the pre-drying processing liquid is supplied to the uppersurface of the substrate W covered with the liquid film of thereplacement liquid. The replacement liquid is a liquid that dissolveswith both the rinse liquid and the pre-drying processing liquid. Forexample, the replacement liquid is IPA or HFE. The replacement liquidmay be a liquid mixture of IPA and HFE or may contain at least one ofIPA and HFE and a component other than those. The IPA and HFE is aliquid that dissolves with both water and a fluorinated hydrocarboncompound.

When the replacement liquid is supplied to the upper surface of thesubstrate W covered with the liquid film of rinse liquid, most of therinse liquid on the substrate W is washed away by the replacement liquidand thus discharged from the substrate W. The small amount of remainingrinse liquid is dissolved in the replacement liquid to be diffused intothe replacement liquid. The diffused rinse liquid is discharged from thesubstrate W together with the replacement liquid. Therefore, the rinseliquid on the substrate W can be efficiently replaced with thereplacement liquid. For the same reason, the replacement liquid on thesubstrate W can be efficiently replaced with the pre-drying processingliquid. This makes it possible to reduce the rinse liquid contained inthe pre-drying processing liquid on the substrate W.

The pre-drying processing liquid nozzle 39 is connected to a nozzlemoving unit 42 that moves the pre-drying processing liquid nozzle 39 atleast in one of the vertical and horizontal directions. The nozzlemoving unit 42 horizontally moves the pre-drying processing liquidnozzle 39 between the processing position, at which the pre-dryingprocessing liquid discharged from the pre-drying processing liquidnozzle 39 is supplied to the upper surface of the substrate W, and thestandby position at which the pre-drying processing liquid nozzle 39 islocated around the processing cup 21 in plan view.

Likewise, the replacing liquid nozzle 43 is connected to a nozzle movingunit 46 that moves the replacing liquid nozzle 43 at least in one of thevertical and horizontal directions. The nozzle moving unit 46horizontally moves the replacing liquid nozzle 43 between the processingposition, at which the replacement liquid discharged from the replacingliquid nozzle 43 is supplied to the upper surface of the substrate W,and the standby position at which the replacing liquid nozzle 43 islocated around the processing cup 21 in plan view.

The processing unit 2 includes a shielding member 51 that is disposedabove the spin chuck 10. FIG. 2 shows an example in which the shieldingmember 51 is a disc-shaped shielding plate. The shielding member 51includes a disc portion 52 that is horizontally disposed above the spinchuck 10. The shielding member 51 is horizontally supported by a tubularsupport shaft 53 that extends upwardly from the center portion of thedisc portion 52. The center line of the disc portion 52 is disposed onthe rotation axis A1 of the substrate W. The lower surface of the discportion 52 corresponds to the lower surface 51L of the shielding member51. The lower surface 51L of the shielding member 51 is an opposingsurface that faces the upper surface of the substrate W. The lowersurface 51L of shielding member 51 is parallel to the upper surface ofthe substrate W, and has an outer diameter that is equal to or greaterthan the diameter of the substrate W.

The shielding member 51 is connected to a shielding memberelevating/lowering unit 54 that vertically elevates or lowers theshielding member 51. The shielding member elevating/lowering unit 54locates the shielding member 51 at an arbitrary position from the upperposition (the position shown in FIG. 2) to the lower position. The lowerposition is the proximity position at which the shielding member 51 islocated at a height in which the lower surface 51L of the shieldingmember 51 comes into proximity to the upper surface of the substrate Wand a scan nozzle such as the chemical liquid nozzle 31 cannot enterbetween the substrate W and the shielding member 51. The upper positionis the separate position at which the shielding member 51 retracts to aheight in which the scan nozzle is able to enter between the shieldingmember 51 and the substrate W.

The plurality of nozzles include a central nozzle 55 that downwardlydischarges a processing fluid such as a processing liquid or aprocessing gas through an upper central opening 61 that is opened at thecenter portion of the lower surface 51L of the shielding member 51. Thecentral nozzle 55 extends vertically along the rotation axis A1. Thecentral nozzle 55 is disposed inside a through-hole that verticallypenetrates the center portion of the shielding member 51. The innercircumferential surface of the shielding member 51 surrounds the outercircumferential surface of the central nozzle 55 with a spacing in theradial direction (in the direction orthogonal to the rotation axis A1).The central nozzle 55 is elevated or lowered together with the shieldingmember 51. The discharge port of the central nozzle 55 to discharge theprocessing liquid is disposed above the upper central opening 61 of theshielding member 51.

The central nozzle 55 is connected to an upper gas piping 56 that guidesan inert gas to the central nozzle 55. The substrate processingapparatus 1 may include an upper thermoregulator 59 that heats or coolsthe inert gas to be discharged from the central nozzle 55. When an uppergas valve 57 interposed in the upper gas piping 56 is opened, the inertgas is continuously discharged downwardly from the discharge port of thecentral nozzle 55 at a flow rate corresponding to the opening degree ofa flow rate adjusting valve 58 that changes the flow rate of the inertgas. The inert gas discharged from the central nozzle 55 is a nitrogengas. The inert gas may be a gas other than the nitrogen gas such as ahelium gas or an argon gas.

The inner circumferential surface of the shielding member 51 and theouter circumferential surface of the central nozzle 55 define a tubularupper gas flow pas sage 62 that extends vertically. The upper gas flowpassage 62 is connected to an upper gas piping 63 that guides the inertgas to the upper central opening 61 of the shielding member 51. Thesubstrate processing apparatus 1 may include an upper thermoregulator 66that heats or cools the inert gas to be discharged from the uppercentral opening 61 of the shielding member 51. When an upper gas valve64 interposed in the upper gas piping 63 is opened, the inert gas iscontinuously discharged downwardly from the upper central opening 61 ofthe shielding member 51 at a flow rate corresponding to the openingdegree of a flow rate adjusting valve 65 that changes the flow rate ofthe inert gas. The inert gas discharged from the upper central opening61 of the shielding member 51 is a nitrogen gas. The inert gas may be agas other than the nitrogen gas such as a helium gas or an argon gas.

The plurality of nozzles include a lower-surface nozzle 71 thatdischarges the processing liquid to the center portion of the lowersurface of the substrate W. The lower-surface nozzle 71 includes anozzle disc portion that is disposed between the upper surface 12 u ofthe spin base 12 and the lower surface of the substrate W, and a nozzlecylindrical portion that downwardly extends from the nozzle discportion. The discharge port of the lower-surface nozzle 71 is opened atthe center portion of the upper surface of the nozzle disc portion. Whenthe substrate W is held on the spin chuck 10, the discharge port of thelower-surface nozzle 71 vertically faces the center portion of the lowersurface of the substrate W.

The lower-surface nozzle 71 is connected to a heating fluid piping 72that guides hot water (pure water at a temperature higher than roomtemperature) serving as an example of heating fluid to the lower-surfacenozzle 71. The pure water supplied to the lower-surface nozzle 71 isheated by a lower heater 75 that is interposed in the heating fluidpiping 72. When a heating fluid valve 73 interposed in the heating fluidpiping 72 is opened, the hot water is discharged continuously upwardlyfrom the discharge port of the lower-surface nozzle 71 at a flow ratecorresponding to the opening degree of a flow rate adjusting valve 74that changes the flow rate of the hot water. This allows the hot waterto be supplied to the lower surface of the substrate W.

Furthermore, the lower-surface nozzle 71 is connected to a cooling fluidpiping 76 that guides cold water (pure water at a temperature lower thanroom temperature) serving as an example of cooling fluid to thelower-surface nozzle 71. The pure water supplied to the lower-surfacenozzle 71 is cooled by a cooler 79 interposed in the cooling fluidpiping 76. When a cooling fluid valve 77 interposed in the cooling fluidpiping 76 is opened, the cold water is continuously discharged upwardlyfrom the discharge port of the lower-surface nozzle 71 at a flow rateassociated with the opening degree of a flow rate adjusting valve 78that changes the flow rate of the cold water. This allows the cold waterto be supplied to the lower surface of the substrate W.

The outer circumferential surface of the lower-surface nozzle 71 and theinner circumferential surface of the spin base 12 define a tubular lowergas flow passage 82 that extends vertically. The lower gas flow passage82 includes a lower central opening 81 that is opened at the centerportion of the upper surface 12 u of the spin base 12. The lower gasflow passage 82 is connected to a lower gas piping 83 that guides theinert gas to the lower central opening 81 of the spin base 12. Thesubstrate processing apparatus 1 may include a lower thermoregulator 86that heats or cools the inert gas to be discharged from the lowercentral opening 81 of the spin base 12. When a lower gas valve 84interposed in the lower gas piping 83 is opened, the inert gas iscontinuously discharged upwardly from the lower central opening 81 ofthe spin base 12 at a flow rate corresponding to the opening degree of aflow rate adjusting valve 85 that changes the flow rate of the inertgas.

The inert gas discharged from the lower central opening 81 of the spinbase 12 is a nitrogen gas. The inert gas may be a gas other than thenitrogen gas such as a helium gas or an argon gas. When the lowercentral opening 81 of the spin base 12 discharges the nitrogen gas withthe substrate W held on the spin chuck 10, the nitrogen gas radiallyflows in all directions between the lower surface of the substrate W andthe upper surface 12 u of the spin base 12. This allows the spacebetween the substrate W and the spin base 12 to be filled with thenitrogen gas.

Next, description will be made below to a pre-drying processing liquidsupplying unit.

FIG. 3 is a schematic view showing the pre-drying processing liquidsupplying unit provided in the substrate processing apparatus 1.

The substrate processing apparatus 1 includes the pre-drying processingliquid supplying unit that supplies the pre-drying processing liquid tothe pre-drying processing liquid nozzle 39 through the pre-dryingprocessing liquid piping 40.

The pre-drying processing liquid supplying unit includes a first tank87A to store the pre-drying processing liquid, a first circulationpiping 88A to circulate the pre-drying processing liquid inside thefirst tank 87A, a first pump 89A to feed the pre-drying processingliquid inside the first tank 87A to the first circulation piping 88A,and a first individual piping 90A that guides the pre-drying processingliquid inside the first circulation piping 88A to the pre-dryingprocessing liquid piping 40. The pre-drying processing liquid supplyingunit further includes a first opening/closing valve 91A to open/closethe inside of the first individual piping 90A, and a first flow rateadjusting valve 92A that changes the flow rate of the pre-dryingprocessing liquid supplied from the first individual piping 90A to thepre-drying processing liquid piping 40.

The pre-drying processing liquid supplying unit includes a second tank87B to store the pre-drying processing liquid, a second circulationpiping 88B to circulate the pre-drying processing liquid inside thesecond tank 87B, a second pump 89B to feed the pre-drying processingliquid inside the second tank 87B to the second circulation piping 88B,and a second individual piping 90B that guides the pre-drying processingliquid inside the second circulation piping 88B to the pre-dryingprocessing liquid piping 40. Furthermore, the pre-drying processingliquid supplying unit includes a second opening/closing valve 91B toopen/close the inside of the second individual piping 90B, and a secondflow rate adjusting valve 92B that changes the flow rate of thepre-drying processing liquid supplied from the second individual piping90B to the pre-drying processing liquid piping 40.

The concentration of the pre-drying processing liquid inside the firsttank 87A (the concentration of the sublimable substance contained in thepre-drying processing liquid) is different from the concentration of thepre-drying processing liquid inside the second tank 87B. Therefore, whenthe first opening/closing valve 91A and the second opening/closing valve91B are opened, the pre-drying processing liquids having mutuallydifferent concentrations are mixed together within the pre-dryingprocessing liquid piping 40, so that the pre-drying processing liquidthat has been uniformly mixed is discharged from the pre-dryingprocessing liquid nozzle 39. Furthermore, when at least one openingdegree of the first flow rate adjusting valve 92A and the second flowrate adjusting valve 92B is changed, the concentration of the pre-dryingprocessing liquid to be discharged from the pre-drying processing liquidnozzle 39 is changed.

The controller 3 sets the opening degrees of the first opening/closingvalve 91A, the second opening/closing valve 91B, the first flow rateadjusting valve 92A, and the second flow rate adjusting valve 92B inaccordance with the concentration of the pre-drying processing liquidspecified in a recipe described below. For example, in the case wherethe concentration of the pre-drying processing liquid specified in therecipe matches the concentration of the pre-drying processing liquidinside the first tank 87A, the first opening/closing valve 91A isopened, and the second opening/closing valve 91B is kept closed. In thecase where the concentration of the pre-drying processing liquidspecified in the recipe has a value between the concentration of thepre-drying processing liquid inside the first tank 87A and theconcentration of the pre-drying processing liquid inside the second tank87B, both the first opening/closing valve 91A and the secondopening/closing valve 91B are opened, and then the opening degrees ofthe first flow rate adjusting valve 92A and the second flow rateadjusting valve 92B are adjusted. This allows the concentration of thepre-drying processing liquid discharged from the pre-drying processingliquid nozzle 39 to be brought close to the concentration of thepre-drying processing liquid specified in the recipe.

FIG. 4 is a block diagram showing the hardware of the controller 3.

The controller 3 is a computer which includes a computer main body 3 aand a peripheral device 3 b which is connected to the computer main body3 a. The computer main body 3 a includes a CPU 93 (central processingunit) which executes various types of commands and a main storage device94 which stores information. The peripheral device 3 b includes anauxiliary storage device 95 which stores information such as a programP, a reading device 96 which reads information from a removable medium Mand a communication device 97 which communicates with other devices suchas a host computer.

The controller 3 is connected to an input device 98 and a display 99.The input device 98 is operated when an operator such as a user or amaintenance operator inputs information to the substrate processingapparatus 1. The information is displayed on the screen of the display99. The input device 98 may be any one of a keyboard, a pointing deviceand a touch panel or may be a device other than those. A touch paneldisplay which serves both as the input device 98 and the display 99 maybe provided in the substrate processing apparatus 1.

The CPU 93 executes the program P stored in the auxiliary storage device95. The program P within the auxiliary storage device 95 may bepreviously installed in the controller 3, may be fed through the readingdevice 96 from the removable medium M to the auxiliary storage device 95or may be fed from an external device such as the host computer to theauxiliary storage device 95 through the communication device 97.

The auxiliary storage device 95 and the removable medium M arenonvolatile memories which retain memory even without power beingsupplied. The auxiliary storage device 95 is, for example, a magneticstorage device such as a hard disk drive. The removable medium M is, forexample, an optical disc such as a compact disc or a semiconductormemory such as a memory card. The removable medium M is an example of acomputer readable recording medium in which the program P is recorded.The removable medium M is a non-transitory tangible recording medium.

The auxiliary storage device 95 stores a plurality of recipes. Therecipe is information which specifies the details of processing,processing conditions and processing procedures of the substrate W. Aplurality of recipes differ from each other in at least one of thedetails of processing, the processing conditions and the processingprocedures of the substrate W. The controller 3 controls the substrateprocessing apparatus 1 such that the substrate W is processed accordingto the recipe designated by the host computer. The controller 3 executesindividual steps described below by controlling the substrate processingapparatus 1. In other words, the controller 3 is programmed to executethe individual steps described below.

Next, description will be made below to an example of processing thesubstrate W according to the first preferred embodiment.

For example, the substrate W to be processed is a semiconductor wafersuch as a silicon wafer. The front surface of the substrate Wcorresponds to the device formation surface on which devices such astransistors or capacitors are formed. The substrate W may be a substrateW having patterns P1 (see FIG. 6A) formed on the front surface of thesubstrate W corresponding to a pattern formation surface, oralternatively, may be a substrate W having no patterns P1 formed on thefront surface of the substrate W. In the latter case, the patterns P1may be formed in a chemical liquid supplying step described below.

FIG. 5 is a process chart for describing an example of processing thesubstrate W according to the first preferred embodiment. FIG. 6A to FIG.6C are schematic views showing the state of the substrate W when theprocessing the substrate W shown in FIG. 5 is being performed.

FIG. 2 and FIG. 5 will be referred to below. FIG. 6A to FIG. 6C will bereferred to as appropriate.

When the substrate W is processed in the substrate processing apparatus1, a carry-in step (step S1 in FIG. 5) is performed to carry thesubstrate W into the chamber 4.

Specifically, while the shielding member 51 is located at the upperposition, all the guards 24 are located at the lower position, and allscan nozzles are located at the standby position, the center robot CR(see FIG. 1) causes a hand H1 to enter the chamber 4 while supportingthe substrate W with the hand H1. Then, the center robot CR places thesubstrate W in the hand H1 on the plurality of chuck pins 11 while thefront surface of the substrate W is directed upwardly. Thereafter, theplurality of chuck pins 11 are pushed against the outer circumferentialsurface of the substrate W to thereby grip the substrate W. The centerrobot CR retracts the hand H1 out of the chamber 4 after having placedthe substrate W on the spin chuck 10.

Next, the upper gas valve 64 and the lower gas valve 84 are opened, andthe upper central opening 61 of the shielding member 51 and the lowercentral opening 81 of the spin base 12 start to discharge the nitrogengas. This allows the space between the substrate W and the shieldingmember 51 to be filled with the nitrogen gas. Likewise, the spacebetween the substrate W and the spin base 12 is filled with the nitrogengas. Meanwhile, the guard elevating/lowering unit 27 elevates at leastone guard 24 from the lower position to the upper position. Thereafter,the spin motor 14 is driven, and the rotation of the substrate W isstarted (step S2 in FIG. 5). This allows the substrate W to be rotatedat a liquid supplying speed.

Next, the chemical liquid supplying step (step S3 in FIG. 5) isperformed to supply a chemical liquid onto the upper surface of thesubstrate W and thereby forma liquid film of the chemical liquid thatcovers the entire upper surface of the substrate W.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 34 moves the chemical liquid nozzle 31 from the standbyposition to the processing position. Thereafter, the chemical liquidvalve 33 is opened, and the chemical liquid nozzle 31 starts todischarge the chemical liquid. When a predetermined time has elapsedafter the chemical liquid valve 33 is opened, the chemical liquid valve33 is closed, so that the discharge of the chemical liquid is stopped.Thereafter, the nozzle moving unit 34 moves the chemical liquid nozzle31 to the standby position.

The chemical liquid discharged from the chemical liquid nozzle 31collides with the upper surface of the substrate W that is rotating atthe liquid supplying speed, and then, flows outwardly along the uppersurface of the substrate W due to centrifugal force. Thus, the chemicalliquid is supplied to the entire upper surface of the substrate W tothereby form the liquid film of the chemical liquid that covers theentire upper surface of the substrate W. While the chemical liquidnozzle 31 is discharging the chemical liquid, the nozzle moving unit 34may move a liquid landing position so that the liquid landing positionof the chemical liquid passes the center portion and the outercircumference portion of the upper surface of the substrate W, oralternatively, may bring the liquid landing position to a standstill atthe center portion.

Next, a rinse liquid supplying step (step S4 in FIG. 5) is performed tosupply pure water serving as an example of rinse liquid to the uppersurface of the substrate W and thereby wash away the chemical liquid onthe substrate W.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 38 moves the rinse liquid nozzle 35 from the standbyposition to the processing position. Thereafter, the rinse liquid valve37 is opened, and the rinse liquid nozzle 35 starts to discharge therinse liquid. Before the pure water starts to be discharged, the guardelevating/lowering unit 27 may vertically move at least one guard 24 inorder to switch the guard 24 that receives the liquid discharged fromthe substrate W. When a predetermined time has elapsed after the rinseliquid valve 37 is opened, the rinse liquid valve 37 is closed, so thatthe discharge of the rinse liquid is stopped. Thereafter, the nozzlemoving unit 38 moves the rinse liquid nozzle 35 to the standby position.

The pure water discharged from the rinse liquid nozzle 35 collides withthe upper surface of the substrate W that is rotating at the liquidsupplying speed, and then, flows outwardly along the upper surface ofthe substrate W due to centrifugal force. The chemical liquid on thesubstrate W is replaced with the pure water discharged from the rinseliquid nozzle 35. This allows a liquid film of the pure water coveringthe entire upper surface of the substrate W to be formed. While therinse liquid nozzle 35 is discharging the pure water, the nozzle movingunit 38 may move a liquid landing position so that the liquid landingposition of the pure water passes the center portion and the outercircumference portion of the upper surface of the substrate W, oralternatively, may bring the liquid landing position to a standstill atthe center portion.

Next, a replacement liquid supplying step (step S5 in FIG. 5) isperformed to supply a replacement liquid that dissolves with both therinse liquid and the pre-drying processing liquid to the upper surfaceof the substrate W and then replace the pure water on the substrate Wwith the replacement liquid.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 46 moves the replacing liquid nozzle 43 from the standbyposition to the processing position. Thereafter, the replacing liquidvalve 45 is opened, and the replacing liquid nozzle 43 starts todischarge the replacement liquid. Before the replacement liquid startsto be discharged, the guard elevating/lowering unit 27 may verticallymove at least one guard 24 in order to switch the guard 24 that receivesthe liquid discharged from the substrate W. When a predetermined timehas elapsed after the replacing liquid valve 45 is opened, the replacingliquid valve 45 is closed, so that the discharge of the replacementliquid is stopped. Thereafter, the nozzle moving unit 46 moves thereplacing liquid nozzle 43 to the standby position.

The replacement liquid discharged from the replacing liquid nozzle 43collides with the upper surface of the substrate W that is rotating atthe liquid supplying speed, and then, flows outwardly along the uppersurface of the substrate W due to centrifugal force. The pure water onthe substrate W is replaced with the replacement liquid discharged fromthe replacing liquid nozzle 43. This allows a liquid film of thereplacement liquid covering the entire upper surface of the substrate Wto be formed. While the replacing liquid nozzle 43 is discharging thereplacement liquid, the nozzle moving unit 46 may move a liquid landingposition so that the liquid landing position of the replacement liquidpasses the center portion and the outer circumference portion of theupper surface of the substrate W, or alternatively, may bring the liquidlanding position to a standstill at the center portion. After the liquidfilm of the replacement liquid covering the entire upper surface of thesubstrate W is formed, the substrate W may be rotated at a paddle speed(e.g., at a speed greater than zero and 20 rpm or less) while thedischarge of the replacement liquid from the replacing liquid nozzle 43is stopped.

Next, a pre-drying processing liquid supplying step (step S6 in FIG. 5)is performed to supply the pre-drying processing liquid to the uppersurface of the substrate W and thereby forma liquid film of thepre-drying processing liquid on the substrate W.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 42 moves the pre-drying processing liquid nozzle 39 from thestandby position to the processing position. Thereafter, the pre-dryingprocessing liquid valve 41 is opened, and the pre-drying processingliquid nozzle 39 starts to discharge the pre-drying processing liquid.Before the pre-drying processing liquid starts to be discharged, theguard elevating/lowering unit 27 may vertically move at least one guard24 in order to switch the guard 24 that receives the liquid dischargedfrom the substrate W. When a predetermined time has elapsed after thepre-drying processing liquid valve 41 is opened, the pre-dryingprocessing liquid valve 41 is closed, so that the discharge of thepre-drying processing liquid is stopped. Thereafter, the nozzle movingunit 42 moves the pre-drying processing liquid nozzle 39 to the standbyposition.

The pre-drying processing liquid discharged from the pre-dryingprocessing liquid nozzle 39 collides with the upper surface of thesubstrate W that is rotating at the liquid supplying speed, and then,flows outwardly along the upper surface of the substrate W due tocentrifugal force. The replacement liquid on the substrate W is replacedwith the pre-drying processing liquid discharged from the pre-dryingprocessing liquid nozzle 39. This allows a liquid film of the pre-dryingprocessing liquid covering the entire upper surface of the substrate Wto be formed. While the pre-drying processing liquid nozzle 39 isdischarging the pre-drying processing liquid, the nozzle moving unit 42may move a liquid landing position so that the liquid landing positionof the pre-drying processing liquid passes the center portion and theouter circumference portion of the upper surface of the substrate W, oralternatively, may bring the liquid landing position to a standstill atthe center portion.

Next, a film thickness reducing step (step S7 in FIG. 5) is performed toremove some of the pre-drying processing liquid on the substrate W andthereby reduce the film thickness (the thickness of the liquid film) ofthe pre-drying processing liquid on the substrate W while maintainingthe state that the entire upper surface of the substrate W is coveredwith the liquid film of the pre-drying processing liquid.

Specifically, with the shielding member 51 located at the lowerposition, the spin motor 14 maintains the rotational speed of thesubstrate W at a film thickness reducing speed. The film thicknessreducing speed may be equal to or different from the liquid supplyingspeed. The pre-drying processing liquid on the substrate W is dischargedoutwardly from the substrate W due to centrifugal force even after thedischarge of the pre-drying processing liquid is stopped. Thus, thethickness of the liquid film of the pre-drying processing liquid on thesubstrate W is reduced. When the pre-drying processing liquid on thesubstrate W is discharged to a certain extent, the amount of thepre-drying processing liquid discharged from the substrate W per unittime is reduced to zero or generally zero. Thereby, the thickness of theliquid film of the pre-drying processing liquid on the substrate W isstabilized at a value corresponding to the rotational speed of thesubstrate W.

Next, a solidified body forming step (step S8 in FIG. 5) is performed tosolidify the pre-drying processing liquid on the substrate W and therebyform a solidified body 101 containing a sublimable substance (see FIG.6B) on the substrate W.

Specifically, with the shielding member 51 located at the lowerposition, the spin motor 14 maintains the rotational speed of thesubstrate W at a solidified body forming speed. The solidified bodyforming speed may be equal to or different from the liquid supplyingspeed. Furthermore, the upper gas valve 57 is opened to cause thecentral nozzle 55 to start discharging the nitrogen gas. In addition toor in place of opening the upper gas valve 57, the opening degree of theflow rate adjusting valve 65 may be changed to increase the flow rate ofthe nitrogen gas discharged from the upper central opening 61 of theshielding member 51.

For example, when the substrate W starts to be rotated at the solidifiedbody forming speed, the evaporation of the pre-drying processing liquidis accelerated, so that some of the pre-drying processing liquid on thesubstrate W evaporates. Since the vapor pressure of the solvent ishigher than that of the sublimable substance corresponding to a solute,the solvent evaporates at an evaporation rate greater than that of thesublimable substance. Therefore, while the concentration of thesublimable substance gradually increases, the film thickness of thepre-drying processing liquid gradually decreases. The freezing point ofthe pre-drying processing liquid increases with increasingconcentrations of the sublimable substance. As can be seen from acomparison between FIG. 6A and FIG. 6B, when the freezing point of thepre-drying processing liquid reaches the temperature of the pre-dryingprocessing liquid, the pre-drying processing liquid starts to solidify,so that the solidified body 101, which corresponds to a solidified filmcovering the entire upper surface of the substrate W, is formed.

Next, a sublimating step (step S9 in FIG. 5) is performed to sublimatethe solidified body 101 on the substrate W and thereby remove thesolidified body 101 from the upper surface of the substrate W.

Specifically, with the shielding member 51 located at the lowerposition, the spin motor 14 maintains the rotational speed of thesubstrate W at a sublimating speed. The sublimating speed may be equalto or different from the liquid supplying speed. Furthermore, when theupper gas valve 57 is closed, the upper gas valve 57 is opened to causethe central nozzle 55 to start to discharge the nitrogen gas. Inaddition to or in place of opening the upper gas valve 57, the openingdegree of the flow rate adjusting valve 65 may be changed to therebyincrease the flow rate of the nitrogen gas discharged from the uppercentral opening 61 of the shielding member 51. When a predetermined timehas elapsed after the substrate W starts to rotate at the sublimatingspeed, the spin motor 14 is stopped and the rotation of the substrate Wis stopped (step S10 in FIG. 5).

For example, when the substrate W starts to rotate at the sublimatingspeed, the solidified body 101 on the substrate W starts to sublimate,so that a gas containing a sublimable substance is generated from thesolidified body 101 on the substrate W. The gas generated from thesolidified body 101 (a gas containing the sublimable substance) radiallyflows through the space between the substrate W and the shielding member51 and is discharged upwardly from the substrate W. Then, after acertain time has elapsed after the sublimating started, all thesolidified body 101 is removed from the substrate W as shown in FIG. 6C.

Next, a carry-out step (step S11 in FIG. 5) is performed to carry thesubstrate W out of the chamber 4.

Specifically, the shielding member elevating/lowering unit 54 elevatesthe shielding member 51 to the upper position, and the guardelevating/lowering unit 27 lowers all the guards 24 to the lowerposition. Furthermore, the upper gas valve 64 and the lower gas valve 84are closed, so that the upper central opening 61 of the shielding member51 and the lower central opening 81 of the spin base 12 stop dischargingthe nitrogen gas. Thereafter, the center robot CR causes the hand H1 toenter the chamber 4. After the plurality of chuck pins 11 release thegripping of the substrate W, the center robot CR supports the substrateW on the spin chuck 10 with the hand H1. Thereafter, while supportingthe substrate W with the hand H1, the center robot CR retracts the handH1 out of the chamber 4. This allows the processed substrate W to becarried out of the chamber 4.

FIG. 7 is a graph showing an example of an image in which the liquidfilm of the pre-drying processing liquid on the substrate W is reducedin thickness by evaporating the solvent.

FIG. 7 employs a solid line to show the thickness of a liquid film whenthe initial concentration of the sublimable substance is equal to areference concentration, an alternate long and short dashed line to showthe thickness of a liquid film when the initial concentration of thesublimable substance is equal to a low concentration, and an alternatelong and two short dashed line to show the thickness of a liquid filmwhen the initial concentration of the sublimable substance is equal to ahigh concentration. The reference concentration is higher than the lowconcentration and lower than the high concentration. The initialconcentration of the sublimable substance refers to the concentration ofthe sublimable substance in the pre-drying processing liquid beforebeing supplied to the substrate W.

If the concentration of the sublimable substance in the pre-dryingprocessing liquid is the same, a thickness T1 of the solidified body 101to be formed on the substrate W (see FIG. 6B) depends on the filmthickness of the pre-drying processing liquid (the thickness of theliquid film) before the solidified body 101 is formed. That is, agreater film thickness of the pre-drying processing liquid results inthe solidified body 101 of a greater thickness being formed, whereas asmaller film thickness of the pre-drying processing liquid results inthe solidified body 101 of a reduced thickness being formed. Therefore,by changing the film thickness of the pre-drying processing liquid, thethickness T1 of the solidified body 101 can be changed.

When the rotational speed of the substrate W increases, the pre-dryingprocessing liquid is discharged from the substrate W due to centrifugalforce, so that the film thickness of the pre-drying processing liquid onthe substrate W is reduced. At this time, if a gas is discharged towardthe upper surface of the substrate W, the pressure of the gas applies tothe pre-drying processing liquid and thus the film thickness of thepre-drying processing liquid on the substrate W is further reduced.However, when the film thickness is reduced to a certain extent, sincethe flow rate within the liquid film will be extremely lowered, even ifthe rotational speed and the flow rate of the gas is increased, the filmthickness will not be greatly varied. Conversely, excessively increasingthe rotational speed or the flow rate of the gas would cause the uppersurface of the substrate W to be partially exposed from the liquid film.

Therefore, the film thickness of the pre-drying processing liquid beforethe solidified body 101 is formed cannot be extremely thinned even ifthe rotational speed of the substrate W or the flow rate of the gas ischanged, so that an extremely thin solidified body 101 cannot be formed.Therefore, to form an extremely thin solidified body 101 covering theentire upper surface of the substrate W (e.g., a solidified body 101greater in thickness than zero and 1 μm or less) or change the thicknessT1 of the solidified body 101 within an extremely thin range (e.g., arange greater than zero and 1 μm or less), the initial concentration ofthe sublimable substance has to be changed.

In FIG. 7, the film thickness of the pre-drying processing liquid beforethe solvent is evaporated is constant regardless of the initialconcentration of the sublimable substance. Furthermore, as shown in FIG.7, if the pre-drying processing liquids are at an equal temperature, theconcentration of the sublimable substance when the solidified body 101starts to precipitate is constant regardless of the initialconcentration of the sublimable substance. Evaporating the solvent toform the solidified body 101 will cause the film thickness of thepre-drying processing liquid to be gradually reduced with increasingconcentrations of the sublimable substance gradually. The freezing pointof the pre-drying processing liquid increases as the concentration ofthe sublimable substance increases. When the freezing point of thepre-drying processing liquid reaches the temperature of the pre-dryingprocessing liquid, the pre-drying processing liquid starts to solidify,so that the solidified body 101 is formed on the substrate W.

As shown in FIG. 7, when the initial concentration of the sublimablesubstance is the reference concentration, the solidified body 101 of areference thickness Tr is formed. Since the pre-drying processing liquidcontains a small amount of sublimable substance when the initialconcentration of the sublimable substance is a low concentration, asolidified body 101 that is thinner than the reference thickness Tr isformed. Since the pre-drying processing liquid contains a greater amountof sublimable substance when the initial concentration of the sublimablesubstance is at a high concentration, a solidified body 101 that isthicker than the reference thickness Tr is formed. Therefore, bycontrolling the initial concentration of the sublimable substance, thethickness T1 of the solidified body 101 can be varied within theextremely thin range.

FIG. 8 is a graph showing an example of the relationship between theinitial concentration of sublimable substance and the thickness T1 ofthe solidified body 101. The vol % in FIG. 8 refers to the volumepercent concentration. When the pre-drying processing liquid changes tothe solidified body 101, the color of the substance on the substrate Wchanges from transparent to non-transparent. If a non-transparentsolidified body 101 is formed when the film thickness of a transparentpre-drying processing liquid is measured by the spectral interference,measurement values will be varied. Values immediately before thevariation are shown in FIG. 8 as the thickness T1 of the solidified body101.

In FIG. 8, the thickness T1 of the solidified body 101 was approximately100 μm when the initial concentration of the sublimable substance was0.5 vol %, and the thickness T1 of the solidified body 101 wasapproximately 200 μm when the initial concentration of the sublimablesubstance was 1.23 vol % The initial concentration of the sublimablesubstance and the thickness T1 of the solidified body 101 have agenerally directly proportional relationship, so that the thickness T1of the solidified body 101 increases at a constant rate as the initialconcentration of the sublimable substance increases. Therefore, bychanging the initial concentration of the sublimable substance, thethickness T1 of the solidified body 101 can be varied within anextremely thin range.

FIG. 9 is a table showing an example of the embedding rate and thecollapse rate of a pattern P1 that were acquired when a plurality ofsamples, on which patterns P1 having similar shapes and strengths hadbeen formed, are processed while the initial concentration of camphorwas being changed. FIG. 10 is a line graph showing the relationshipbetween the concentration of camphor and the collapse rate of thepattern P1 in FIG. 9.

FIG. 9 and FIG. 10 show the collapse rate of the pattern P1 when thesublimable substance is camphor, and the solvent is IPA. Among themeasurement condition 1-1 to measurement condition 1-13 shown in FIG. 9and FIG. 10, the conditions other than the initial concentration ofcamphor are the same. The wt % in FIG. 9 shows the mass percentconcentration. The same applies to other figures such as FIG. 14.

The collapse rate of the pattern P1 is acquired by multiplying a ratioof the number of collapsed patterns P1 to the total number of patternsP1 by 100. The embedding rate is acquired by multiplying a ratio of thethickness T1 of the solidified body 101 (see FIG. 6B) to a height Hp ofthe pattern P1 (see FIG. 6B) by 100. That is, the embedding rate isdetermined by the calculation equation, ((the thickness T1 of thesolidified body 101/the height Hp of the pattern P1)×100).

As shown for measurement condition 1-1 in FIG. 9, when the initialconcentration of camphor was 0.52 wt %, the collapse rate of the patternP1 was 83.5%.

As shown for measurement condition 1-2 in FIG. 9, when the initialconcentration of camphor was 0.62 wt %, the collapse rate of the patternP1 was 83.1%.

As shown for measurement condition 1-3 in FIG. 9, when the initialconcentration of camphor was 0.69 wt %, the collapse rate of the patternP1 was 76.2%.

As shown for measurement condition 1-4 in FIG. 9, when the initialconcentration of camphor was 0.78 wt %, the collapse rate of the patternP1 was 36.1%.

As shown for measurement condition 1-13 in FIG. 9, when the initialconcentration of camphor was 7.76 wt %, the collapse rate of the patternP1 was 91.0%.

As shown for measurement condition 1-12 in FIG. 9, when the initialconcentration of camphor was 4.03 wt %, the collapse rate of the patternP1 was 91.7%.

As shown for measurement condition 1-11 in FIG. 9, when the initialconcentration of camphor was 2.06 wt %, the collapse rate of the patternP1 was 87.0%.

As shown for measurement condition 1-10 in FIG. 9, when the initialconcentration of camphor was 1.55 wt %, the collapse rate of the patternP1 was 46.8%.

As can be seen from FIG. 9 and FIG. 10, when the initial concentrationof camphor increases from 0.62 wt % to 0.69 wt %, the collapse rate ofthe pattern P1 decreases (measurement condition 1-2 to measurementcondition 1-3). In addition, when the initial concentration of camphorincreases from 0.69 wt % to 0.78 wt %, the collapse rate of the patternP1 abruptly decreases (measurement condition 1-3 to measurementcondition 1-4).

Meanwhile, when the initial concentration of camphor decreases from 2.06wt % to 1.55 wt %, the collapse rate of the pattern P1 abruptlydecreases (measurement condition 1-11 to measurement condition 1-10).

Therefore, the initial concentration of camphor is preferably greaterthan 0.62 wt % and less than 2.06 wt %, more preferably 0.78 wt % orgreater and less than 2.06 wt %.

Within the range of the initial concentration of camphor being greaterthan 0.62 wt % and less than 2.06 wt %, the collapse rate of the patternP1 is less than 87.0%.

Within the range of the initial concentration of camphor being 0.78 wt %or greater and 1.55 wt % or less, the collapse rate of the pattern P1 is46.8% or less.

Within the range of the initial concentration of camphor being 0.89 wt %or greater and 1.24 wt % or less, the collapse rate of the pattern P1 is17.6% or less. The collapse rate of the pattern P1 was 8.32%, that is,the smallest when the initial concentration of camphor was 0.89 wt %.

Therefore, the initial concentration of camphor may be 0.78 wt % orgreater and 1.55 wt % or less, or may also be 0.89 wt % or greater and1.24 wt % or less.

FIG. 11 is a line graph showing the relationship between the embeddingrate and the collapse rate of the pattern P1 in FIG. 9.

As shown for measurement condition 1-1 in FIG. 9, when the embeddingrate was 65%, the collapse rate of the pattern P1 was 83.5%.

As shown for measurement condition 1-2 in FIG. 9, when the embeddingrate was 76%, the collapse rate of the pattern P1 was 83.1%.

As shown for measurement condition 1-3 in FIG. 9, when the embeddingrate was 83%, the collapse rate of the pattern P1 was 76.2%.

As shown for measurement condition 1-4 in FIG. 9, when the embeddingrate was 91%, the collapse rate of the pattern P1 was 36.1%.

As shown for measurement condition 1-13 in FIG. 9, when the embeddingrate was 797%, the collapse rate of the pattern P1 was 91.0%.

As shown for measurement condition 1-12 in FIG. 9, when the embeddingrate was 418%, the collapse rate of the pattern P1 was 91.7%.

As shown for measurement condition 1-11 in FIG. 9, when the embeddingrate was 219%, the collapse rate of the pattern P1 was 87.0%.

As shown for measurement condition 1-10 in FIG. 9, when the embeddingrate was 168%, the collapse rate of the pattern P1 was 46.8%.

As can be seen from FIG. 9 and FIG. 11, when the embedding rateincreases from 76% to 83%, the collapse rate of the pattern P1 decreases(measurement condition 1-2 to measurement condition 1-3). In addition,when the embedding rate increases from 83% to 91%, the collapse rate ofthe pattern P1 abruptly decreases (measurement condition 1-3 tomeasurement condition 1-4).

Meanwhile, when the embedding rate decreases from 219% to 168%, thecollapse rate of the pattern P1 abruptly decreases (measurementcondition 1-11 to measurement condition 1-10).

Therefore, the embedding rate is preferably greater than 76% and lessthan 219%, more preferably 83% or greater and less than 219%.

Within the range of the embedding rate being greater than 76% and lessthan 219%, the collapse rate of the pattern P1 is less than 87.0%.

Within the range of the embedding rate being 91% or greater and 168% orless, the collapse rate of the pattern P1 is 46.8% or less.

Within the range of the embedding rate being 102% or greater and 138% orless, the collapse rate of the pattern P1 is 17.6% or less. The collapserate of the pattern P1 was 8.32%, that is, the smallest when theembedding rate was 102%.

Therefore, the embedding rate may be 91% or greater and 168% or less andmay also be 102% or greater and 138% or less.

As described above, the initial concentration of camphor is preferablygreater than 0.62 wt % and less than 2.06 wt %. As shown in FIG. 9, whenthe initial concentration of camphor is 0.62 wt %, the embedding rate is76%. When the initial concentration of camphor is 2.06 wt %, theembedding rate is 219%. Therefore, in the example, setting the initialconcentration of camphor to a value within a preferable range willresult in the embedding rate being automatically set to a value within apreferable range.

FIG. 12A and FIG. 12B are schematic views for describing a possiblemechanism for a phenomenon that an excessively thick solidified body 101will lead to a higher collapse rate of the pattern P1. FIG. 13A and FIG.13B are schematic views for describing a possible mechanism for aphenomenon that an excessively thin solidified body 101 will lead to ahigher collapse rate of the pattern P1.

As shown in FIG. 11, an excessively thick solidified body 101 (anexcessively high embedding rate) will lead to a higher collapse rate ofthe pattern P1. Additionally, although the collapse rate of the patternP1 may be low in some cases even when the thickness T1 of the solidifiedbody 101 is less than the height Hp of the pattern P1, an excessivelythin solidified body 101 (an excessively low embedding rate) will leadto a higher collapse rate of the pattern P1. Hereinafter, descriptionwill be made for a possible mechanism for these phenomena.

First, description will be made for a possible mechanism for aphenomenon that an excessively thick solidified body 101 will lead to ahigher collapse rate of the pattern P1.

As the evaporation of IPA contained in the pre-drying processing liquidproceeds, the concentration of camphor in the pre-drying processingliquid gradually increases, so that the freezing point of the pre-dryingprocessing liquid gradually increases. When the freezing point of thepre-drying processing liquid reaches the temperature of the pre-dryingprocessing liquid, the pre-drying processing liquid starts to solidify,so that the solidified body 101 containing camphor is formed on thesubstrate W.

When the embedding rate is 100% or greater, that is, when the thicknessT1 of the solidified body 101 (see FIG. 6B) is equal to or greater thanthe height Hp of the pattern P1 (see FIG. 6B), the pre-drying processingliquid is found not only between patterns P1 but also above the patternsP1 before the solidified body 101 is formed. For the substrate W such asa semiconductor wafer, since adjacent two projected patterns P1 have anarrow spacing, the freezing point of the pre-drying processing liquidlocated between the patterns P1 is lowered. Therefore, the freezingpoint of the pre-drying processing liquid located between the patternsP1 is lower than the freezing point of the pre-drying processing liquidlocated above the patterns P1.

When the freezing point of the pre-drying processing liquid locatedabove the patterns P1 is higher than the freezing point of thepre-drying processing liquid located between the patterns P1, thepre-drying processing liquid starts to solidify at a position other thanbetween the patterns P1. Specifically, as shown in FIG. 12A, the crystalnucleus of camphor is generated in the surface layer of the pre-dryingprocessing liquid, that is, in a liquid layer located within the rangefrom the upper surface of the pre-drying processing liquid (fluidsurface) to the upper surface of the pattern P1, so that the crystalnucleus gradually grows. Then, when a certain time has elapsed, theentire surface layer of the pre-drying processing liquid is solidifiedinto a solidified body 101.

When the freezing point of the pre-drying processing liquid locatedbetween the patterns P1 is lower than the freezing point of thepre-drying processing liquid located above the patterns P1, as shown inFIG. 12B, the pre-drying processing liquid located between the patternsP1 may not be solidified but remains unchanged in the state of liquid.In this case, an interface between a solid (the solidified body 101) anda liquid (the pre-drying processing liquid) is formed in the vicinity ofthe pattern P1. FIG. 12B shows the state of an unclear interface betweensolid and liquid that is located between the patterns P1.

Solid and liquid have mutually different surface free energies. When anunclear interface between a solid (the solidified body 101) and a liquid(the pre-drying processing liquid) is located between the patterns P1, aforce caused by Laplace pressure is applied to the patterns P1. At thistime, the force applied to the patterns P1 increases as the solidifiedbody 101 becomes thicker. Therefore, when the solidified body 101 isexcessively thick, a collapsing force to collapse the patterns P1 wouldexceed the strength of the patterns P1, so that the collapse rate of thepattern P1 becomes higher. It is thought that such a mechanism raisesthe collapse rate of the pattern P1.

Next, description will be made for a possible mechanism for a phenomenonthat the collapse rate of the pattern P1 becomes lower even for anembedding rate of less than 100%.

When the solidified body 101 is formed, the upper surface (fluidsurface) of the pre-drying processing liquid gradually approaches thelower end of the pattern P1 as the evaporation of IPA proceeds. When thethickness T1 of the solidified body 101 is significantly less than theheight Hp of the pattern P1, as shown in FIG. 13A, the upper surface ofthe pre-drying processing liquid moves to between two adjacent projectedpatterns P1 before the entire pre-drying processing liquid issolidified. That is, an interface between a gas and a liquid (thepre-drying processing liquid) moves to between the patterns P1. For thatreason, it is thought that a force caused by the surface tension of thepre-drying processing liquid is applied to the patterns P1, and thus thepattern P1 is collapsed. Then, as shown in FIG. 13B, it is thought thatthe solidified body 101 is formed with the pattern P1 collapsed.

It is also thought that the interface between gas and liquid may move tobetween the patterns P1 when the thickness T1 of the solidified body 101is slightly less than the height Hp of the pattern P1. However, in thiscase, it is thought that the crystal nucleus of camphor has already beenformed between the patterns P1, and the crystal nucleus has grown to acertain extent. In this case, the gradient of the pattern P1 isrestricted by a large crystal nucleus, and thus the patterns P1 areunlikely to collapse. It is thought that such a mechanism would lowerthe collapse rate of the pattern P1 even when the thickness T1 of thesolidified body 101 is somewhat less than the height Hp of the patternP1.

As described above, an excessively thin or thick solidified body 101would lower the collapse rate of the pattern P1. In other words, tolower the collapse rate of the pattern P1 of the substrate W afterhaving been dried, the thickness of the solidified body 101 has anappropriate range. For example, by setting the solidified body 101 to avalue within the range that was described referring to FIG. 9, thecollapse rate of the pattern P1 of the substrate W after having beendried can be lowered. This allows the substrate W to be dried whilereducing the collapse rate of the pattern P1.

Next, description will be made to measurement results acquired on othersamples.

FIG. 14 to FIG. 16 are a table showing an example of the collapse ratesof patterns P1 that were acquired when a plurality of samples, on whichpatterns P1 having similar shapes and strengths had been formed, wereprocessed while the initial concentration of camphor was being changed.

FIG. 14 shows the collapse rate of the pattern P1 when the sublimablesubstance is camphor and the solvent is IPA. FIG. 15 shows the collapserate of the pattern P1 when the sublimable substance is camphor and thesolvent is acetone. FIG. 16 shows the collapse rate of the pattern P1when the sublimable substance is camphor and the solvent is PGEE.

Among measurement condition 2-1 to measurement condition 2-5 shown inFIG. 14, the conditions other than the initial concentration of camphorare the same. Likewise, among measurement condition 3-1 to measurementcondition 3-13 shown in FIG. 15, the conditions other than the initialconcentration of camphor are the same. Further, among measurementcondition 4-1 to measurement condition 4-8 shown in FIG. 16, theconditions other than the initial concentration of camphor are the same.

For the measurements in FIG. 14 to FIG. 16, similar samples wereemployed. The strengths of the patterns P1 of the samples used for themeasurements in FIG. 14 to FIG. 16 are different from the strengths ofthe patterns P1 of the samples used for the measurements in FIG. 9.Therefore, although FIG. 9 and FIG. 14 both show the collapse rate ofthe pattern P1 when the sublimable substance is camphor and the solventis IPA, the collapse rates shown in FIG. 9 and FIG. 14 cannot be simplycompared with each other because the strengths of the patterns P1 usedfor the measurements are different.

FIG. 17 is a line graph showing the relationship between theconcentration of camphor and the collapse rate of the pattern P1 in FIG.14. FIG. 18 is a line graph showing the relationship between theconcentration of camphor and the collapse rate of the pattern P1 in FIG.15. FIG. 19 is a line graph showing the relationship between theconcentration of camphor and the collapse rate of the pattern P1 in FIG.16.

First, referring to FIG. 14 and FIG. 17, description will be made for anexample of the relationship between the initial concentration of camphorand the collapse rate of the pattern P1 when the solvent is IPA.

As shown for measurement condition 2-1 in FIG. 14, when the initialconcentration of camphor was 0.89 wt %, the collapse rate of the patternP1 was 91.7%.

As shown for measurement condition 2-2 in FIG. 14, when the initialconcentration of camphor was 0.96 wt %, the collapse rate of the patternP1 was 58.4%.

As shown for measurement condition 2-3 in FIG. 14, when the initialconcentration of camphor was 1.13 wt %, the collapse rate of the patternP1 was 37.3.

As shown for measurement condition 2-4 in FIG. 14, when the initialconcentration of camphor was 1.38 wt %, the collapse rate of the patternP1 was 50.6%.

As shown for measurement condition 2-5 in FIG. 14, when the initialconcentration of camphor was 1.55 wt %, the collapse rate of the patternP1 was 95.3%.

As can be seen from FIG. 14 and FIG. 17, when the initial concentrationof camphor increases from 0.89 wt % to 0.96 wt %, the collapse rate ofthe pattern P1 abruptly decreases (measurement condition 2-1 tomeasurement condition 2-2). When the initial concentration of camphordecreases from 1.55 wt % to 1.38 wt %, the collapse rate of the patternP1 also abruptly decreases (measurement condition 2-5 to measurementcondition 2-4).

Within the range of the initial concentration of camphor being 0.96 wt %or greater and 1.38 wt % or less, the collapse rate of the pattern P1 is58.4% or less. Therefore, when the solvent is IPA, the initialconcentration of camphor is preferably greater than 0.89 wt % and lessthan 1.55 wt %, more preferably 0.96 wt % or greater and 1.38 wt % orless.

Next, referring to FIG. 15 and FIG. 18, description will be made for anexample of the relationship between the initial concentration of camphorand the collapse rate of the pattern P1 when the solvent is acetone.

As shown for measurement condition 3-3 in FIG. 15, when the initialconcentration of camphor was 0.62 wt %, the collapse rate of the patternP1 was 86.6%.

As shown for measurement condition 3-4 in FIG. 15, when the initialconcentration of camphor was 0.69 wt %, the collapse rate of the patternP1 was 60.2%.

As shown for measurement condition 3-9 in FIG. 15, when the initialconcentration of camphor was 1.04 wt %, the collapse rate of the patternP1 was 99.7%.

As shown for measurement condition 3-8 in FIG. 15, when the initialconcentration of camphor was 0.96 wt %, the collapse rate of the patternP1 was 82.2%.

As shown for measurement condition 3-7 in FIG. 15, when the initialconcentration of camphor was 0.89 wt %, the collapse rate of the patternP1 was 76.4%.

As can be seen from FIG. 15 and FIG. 18, when the initial concentrationof camphor increases from 0.62 wt % to 0.69 wt %, the collapse rate ofthe pattern P1 abruptly decreases (measurement condition 3-3 tomeasurement condition 3-4). When the initial concentration of camphordecreases from 1.04 wt % to 0.96 wt %, the collapse rate of the patternP1 also abruptly decreases (measurement condition 3-9 to measurementcondition 3-8).

However, within the range of the initial concentration of camphor being0.96 wt % or greater and 1.04 wt % or less, the collapse rate of thepattern P1 is not too low. When the initial concentration of camphordecreases from 0.96 wt % to 0.89 wt % (measurement condition 3-8 tomeasurement condition 3-7), the collapse rate of the pattern P1 abruptlydecreases, and further the collapse rate of the pattern P1 iscomparatively low. Therefore, when the solvent is acetone, the initialconcentration of camphor is preferably greater than 0.62 wt % and 0.96wt % or less.

Next, referring to FIG. 16 and FIG. 19, description will be made for anexample of the relationship between the initial concentration of camphorand the collapse rate of the pattern P1 when the solvent is PGEE.

As shown for measurement condition 4-3 in FIG. 16, when the initialconcentration of camphor was 3.06 wt %, the collapse rate of the patternP1 was 98.9%.

As shown for measurement condition 4-4 in FIG. 16, when the initialconcentration of camphor was 3.55 wt %, the collapse rate of the patternP1 was 88.3%.

As shown for measurement condition 4-5 in FIG. 16, when the initialconcentration of camphor was 4.23 wt %, the collapse rate of the patternP1 was 79.4%.

As shown for measurement condition 4-8 in FIG. 16, when the initialconcentration of camphor was 9.95 wt %, the collapse rate of the patternP1 was 99.5%.

As shown for measurement condition 4-7 in FIG. 16, when the initialconcentration of camphor was 6.86 wt %, the collapse rate of the patternP1 was 62.1%.

As shown for measurement condition 4-6 in FIG. 16, when the initialconcentration of camphor was 5.23 wt %, the collapse rate of the patternP1 was 57.5%.

As can be seen from FIG. 15 and FIG. 18, when the initial concentrationof camphor increases from 3.06 wt % to 3.55 wt % (measurement condition4-3 to measurement condition 4-4), the collapse rate of the pattern P1abruptly decreases, however, within the range, the collapse rate of thepattern P1 is not too low. When the initial concentration of camphorincreases from 3.55 wt % to 4.23 wt % (measurement condition 4-4 tomeasurement condition 4-5), the collapse rate of the pattern P1 abruptlydecreases, and further the collapse rate of the pattern P1 iscomparatively low.

Additionally, when the initial concentration of camphor decreases from9.95 wt % to 6.86 wt % (measurement condition 4-8 to measurementcondition 4-7), the collapse rate of the pattern P1 abruptly decreases,however, within the range, included is such a case where the collapserate of the pattern P1 is not too low. That is, the collapse rate of thepattern P1 is low when the initial concentration of camphor is near 6.86wt %, however, the collapse rate of the pattern P1 is high when theinitial concentration of camphor is near 9.95 wt %.

When the initial concentration of camphor decreases from 6.86 wt % to5.23 wt % (measurement condition 4-7 to measurement condition 4-6), thecollapse rate of the pattern P1 gradually decreases. Therefore, when thesolvent is PGEE, the initial concentration of camphor is preferablygreater than 3.55 wt % and 6.86 wt % or less.

FIG. 20 is a graph acquired by overlapping the lines of FIG. 17 to FIG.19. In FIG. 20, the lines of FIG. 17 (IPA) are shown in solid lines, thelines of FIG. 18 (acetone) are shown in broken lines, and the lines ofFIG. 19 (PGEE) are shown in alternate long and short dashed lines.

When the solvent was IPA and the initial concentration of camphor was1.13 wt %, the collapse rate of the pattern P1 was 37.3%, that is, thesmallest (measurement condition 2-3).

When the solvent was acetone and the initial concentration of camphorwas 0.78 wt %, the collapse rate of the pattern P1 was 57.6%, that is,the smallest (measurement condition 3-5).

When the solvent was PGEE and the initial concentration of camphor was5.23 wt %, the collapse rate of the pattern P1 was 57.5%, that is, thesmallest (measurement condition 4-6).

In other words, the initial concentration of camphor at the lowestcollapse rate of the pattern P1 was as follows: 0.78 wt % when thesolvent was acetone; 1.13 wt % when the solvent was IP; and 5.23 wt %when the solvent was PGEE. In a comparison in which attention is focusedon these solvents, the initial concentration of camphor at the lowestcollapse rate of the pattern P1 increases as the vapor pressure of thesolvent decreases. That is, if the solvent easily evaporates, theconcentration of the sublimable substance contained in the pre-dryingprocessing liquid is not always required to increase. Conversely, if thesolvent does not easily evaporate, the concentration of the sublimablesubstance contained in the pre-drying processing liquid is required toincrease.

The present invention makes it necessary to evaporate the solvent fromthe pre-drying processing liquid and thereby form the solidified body101 containing the sublimable substance on the front surface of thesubstrate W. Thus, for example, a step of selecting a solvent dependingon the vapor pressure of the sublimable substance may be performed.

As described above, according to the measurement results of FIG. 9,setting the initial concentration of camphor to a value within apreferable range will result in the embedding rate being automaticallyset to a value within a preferable range. Therefore, for themeasurements of FIG. 14 to FIG. 16, it is thought that setting theinitial concentration of camphor to a value within the preferable rangewill result in the embedding rate being automatically set to a valuewithin the preferable range. It is thought that this lowers the collapserate of the pattern P1.

However, it is thought that setting the initial concentration of camphorto a value within the preferable range would not always result in theembedding rate being set to a value within the preferable rangedepending on the shape or strength of the pattern P1. Likewise, it isalso thought that setting the embedding rate to a value within thepreferable range would not always result in the initial concentration ofcamphor being set to a value within the preferable range depending onthe shape or strength of the pattern P1.

As described above, in the first preferred embodiment, the pre-dryingprocessing liquid that contains the sublimable substance, whichcorresponds to a solute, and the solvent is supplied to the frontsurface of the substrate W on which the pattern P1 has been formed.Thereafter, the solvent is evaporated from the pre-drying processingliquid. This allows the solidified body 101 containing the sublimablesubstance to be formed on the front surface of the substrate W.Thereafter, the solidified body 101 on the substrate W is changed to gaswithout passing through to a liquid. This allows the solidified body 101to be removed from the front surface of the substrate W. Therefore, thecollapse rate of the pattern P1 can be lowered as compared with aconventional drying method such as the spin dry.

Evaporating the solvent from the pre-drying processing liquid will causethe solidified body 101 containing the sublimable substance to be formedon the front surface of the substrate W. The embedding rate when thesolidified body 101 is formed is greater than 76 and less than 219. Asdescribed above, with the embedding rate being out of the range, thenumber of collapsed patterns P1 would increase depending on the strengthof the pattern P1. Conversely, when the embedding rate is within therange, the number of collapsed patterns P1 can be reduced even when thestrength of the pattern P1 is low. Therefore, even when the strength ofthe pattern P1 is low, the collapse rate of the pattern P1 can belowered.

Next, description will be made below for a second preferred embodiment.

The second preferred embodiment is different from the first preferredembodiment mainly in that in addition to the sublimable substance andthe solvent, an adsorbent substance is contained in the pre-dryingprocessing liquid.

In FIG. 21 to FIG. 23F below, the same components as those shown in FIG.1 to FIG. 20 will be given the same reference symbols as those of FIG. 1and so on, and will not be explained repeatedly.

FIG. 21 is a schematic view showing the inside of the processing unit 2provided in the substrate processing apparatus 1 according to the secondpreferred embodiment, when viewed horizontally.

The plurality of nozzles in the processing unit 2 further include asecond chemical liquid nozzle 31B that discharges, to the upper surfaceof the substrate W, a chemical liquid that is different from thechemical liquid discharged from the chemical liquid nozzle 31corresponding to the first chemical liquid nozzle. The second chemicalliquid nozzle 31B may be a scan nozzle that is horizontally movablewithin the chamber 4, or may also be a fixed nozzle that is secured tothe partition wall 5 of the chamber 4. FIG. 21 shows an example in whichthe second chemical liquid nozzle 31B is a scan nozzle.

The second chemical liquid nozzle 31B is connected to a second chemicalliquid piping 32B that guides the chemical liquid to the second chemicalliquid nozzle 31B. When a second chemical liquid valve 33B interposed inthe second chemical liquid piping 32B is opened, the chemical liquid iscontinuously discharged downwardly from the discharge port of the secondchemical liquid nozzle 31B. As long as the chemical liquid dischargedfrom the second chemical liquid nozzle 31B is different from thechemical liquid discharged from the chemical liquid nozzle 31, thechemical liquid discharged from the second chemical liquid nozzle 31Bmay be a liquid containing at least one of sulfuric acid, nitric acid,hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid,ammonia water, a hydrogen peroxide solution, organic acid (e.g., such ascitric acid or oxalic acid), organic alkaline (e.g., such as TMAH:tetramethyl ammonium hydroxide), a surface-active agent, and a corrosioninhibitor, or alternatively, may be a liquid other than that.

The second chemical liquid nozzle 31B is connected to a nozzle movingunit 34B that moves the second chemical liquid nozzle 31B at least inone of the vertical and horizontal directions. The nozzle moving unit34B horizontally moves the second chemical liquid nozzle 31B between theprocessing position at which the chemical liquid discharged from thesecond chemical liquid nozzle 31B is supplied to the upper surface ofthe substrate W and the standby position at which the second chemicalliquid nozzle 31B is located around the processing cup 21 in plan view.

As described above, the pre-drying processing liquid contains theadsorbent substance in addition to the sublimable substance and thesolvent. The pre-drying processing liquid is a solution that containsthe sublimable substance corresponding to a solute, the solvent thatdissolves with the sublimable substance, and the adsorbent substanceadsorbed to the surface of the pattern P1 (see FIG. 23A). The sublimablesubstance, the solvent, and the adsorbent substance are different intype from each other. The adsorbent substance is a substance thatdissolves with at least one of the sublimable substance and the solvent.

The solvent is a liquid of dissolved substance that dissolves with thesublimable substance. The concentration of the dissolved substance inthe pre-drying processing liquid is higher than the concentration of thesublimable substance in the pre-drying processing liquid and higher thanthe concentration of the adsorbent substance in the pre-dryingprocessing liquid. The concentration of the adsorbent substance in thepre-drying processing liquid may be equal to the concentration of thesublimable substance in the pre-drying processing liquid, or may also bedifferent from the concentration of the sublimable substance in thepre-drying processing liquid.

The adsorbent substance has amphiphilic molecules that contain both thehydrophilic group and the hydrophobic group. The adsorbent substance maybe a surface-active agent. As long as the adsorbent substance isdifferent from the sublimable substance and the solvent, the adsorbentsubstance may be a substance that changes from solid to gas withoutpassing through to a liquid at normal temperature or at normal pressure(i.e., a substance having sublimability), or alternatively, may be asubstance other than those. The sublimable substance may be ahydrophobic substance or a hydrophilic substance, or may also be anamphiphilic molecule. Likewise, the solvent may be a hydrophobicsubstance or a hydrophilic substance, or may also have amphiphilicmolecules.

When the sublimable substance is a hydrophilic substance or hasamphiphilic molecules, the adsorbent substance may be higher inhydrophilicity than the sublimable substance. In other words, thesolubility of the adsorbent substance in water may be higher than thesolubility of the sublimable substance in water. When the sublimablesubstance is a hydrophobic substance or has amphiphilic molecules, thesublimable substance may be higher in hydrophobicity than the adsorbentsubstance. In other words, the solubility of the sublimable substance inoil may be higher than the solubility of the adsorbent substance in oil.The same applies to the solvent.

When the surface of the pattern P1 is hydrophilic and the adsorbentsubstance is higher in hydrophilicity than the sublimable substance, theadsorbent substance is more easily adsorbed to the surface of thepattern P1 than the sublimable substance is. The hydrophilic group ofthe adsorbent substance is adhered to the surface of the pattern P1,while the sublimable substance is adhered to the hydrophobic group ofthe adsorbent substance adhered to the surface of the pattern P1. Whenthe surface of the pattern P1 is hydrophobic, and the sublimablesubstance is higher in hydrophobicity than the adsorbent substance, thesublimable substance is more easily adsorbed to the surface of thepattern P1 than the adsorbent substance is. Therefore, whether thesurface of the pattern P1 is either hydrophilic or hydrophobic, it ispossible to locate the sublimable substance on the surface of thepattern P1 or in its vicinity.

The freezing point of the sublimable substance is higher than the roomtemperature. The freezing point of the sublimable substance may behigher than the boiling point of the solvent. The freezing point of thesolvent is lower than the room temperature. The freezing point of theadsorbent substance may be the room temperature or may be different fromthe room temperature. When the freezing point of the adsorbent substanceis higher than the room temperature, the freezing point of the adsorbentsubstance may be equal to the freezing point of the sublimable substanceor may be different from the freezing point of the sublimable substance.The freezing point of the pre-drying processing liquid is lower than theroom temperature (23° C. or a value in its vicinity). The freezing pointof the pre-drying processing liquid may be equal to or greater than theroom temperature.

The vapor pressure of the solvent is higher than that of the sublimablesubstance and higher than that of the adsorbent substance. The vaporpressure of the adsorbent substance may be equal to that of thesublimable substance or may be different from that of the sublimablesubstance. The solvent evaporates from the pre-drying processing liquidat an evaporation rate that is greater than the evaporation rates of thesublimable substance and the adsorbent substance. The freezing point ofthe pre-drying processing liquid rises as the solvent evaporates. Whenthe freezing point of the pre-drying processing liquid rises to the roomtemperature, the pre-drying processing liquid changes from liquid tosolid. This allows the solidified body 101 containing the sublimablesubstance to be formed.

Hereinafter, description will be made for an example in which thesublimable substance is camphor, the solvent is IPA, and the adsorbentsubstance is tertiary butyl alcohol. In the descriptions below, thepre-drying processing liquid is a solution of camphor, IPA, and tertiarybutyl alcohol. In place of camphor, naphthalene may be contained in thepre-drying processing liquid. In place of IPA, acetone or PGEE may becontained in the pre-drying processing liquid. In place of tertiarybutyl alcohol, cyclohexanol may be contained in the pre-dryingprocessing liquid.

The molecule of camphor includes a hydrocarbon group, that is ahydrophobic group, and a carbonyl group that is a hydrophilic group. Themolecule of IPA includes an alkyl group, that is a hydrophobic group,and a hydroxyl group that is a hydrophilic group. The molecule oftertiary butyl alcohol also includes an alkyl group, that is ahydrophobic group, and a hydroxyl group that is a hydrophilic group. TheIPA and tertiary butyl alcohol are amphiphilic molecules. Strictlyspeaking, the camphor is amphiphilic molecule, but it is regarded as ahydrophobic substance because the camphor has a significantly lowersolubility in water as compared with tertiarybutyl alcohol. The camphoris higher in hydrophobicity than tertiary butyl alcohol.

The first tank 87A and the second tank 87B shown in FIG. 3 storepre-drying processing liquids that are the same in the concentration ofthe adsorbent substance and different in the concentration of sublimablesubstance. Therefore, even when the pre-drying processing liquidsupplied from the first tank 87A is mixed with the pre-drying processingliquid supplied from the second tank 87B, the resulting concentration ofthe adsorbent substance in the mixed pre-drying processing liquid isunchanged from the concentration of the adsorbent substance in thepre-drying processing liquid inside the first tank 87A and the secondtank 87B. The initial concentration of the sublimable substance in thepre-drying processing liquid inside the first tank 87A and the secondtank 87B may be set to the same value as that of the first preferredembodiment or may be set to a value different from the value of thefirst preferred embodiment.

Next, description will be made below for an example of processing thesubstrate W according to the second preferred embodiment.

FIG. 22 is a process chart for describing an example of processing thesubstrate W according to the second preferred embodiment. In thedescriptions below, FIG. 21 and FIG. 22 will be referred to.

In the example of processing the substrate W according to the secondpreferred embodiment, in place of step S3 to step S4 shown in FIG. 5,step S3-1 to step S4-2 shown in FIG. 22 are performed. The steps otherthan those are the same as step S1 to step S2 and step S5 to step S11shown in FIG. 5. Therefore, description will be made below for step S3-1to step S4-2.

Additionally, description will be made below for an example in whichhydrofluoric acid and SC1 (a liquid mixture of ammonia, hydrogenperoxide, and water) are sequentially supplied to a silicon wafercorresponding to the substrate W. The hydrofluoric acid is supplied tothe silicon wafer to thereby remove, from the silicon wafer, a naturaloxidation film formed on the silicon wafer. This allows the silicon tobe exposed on the surface of the pattern P1. Thereafter, SC1 is suppliedto the silicon wafer. The silicon exposed on the surface of the patternP1 is changed to silicon oxide when brought into contact with SC1. Thiscauses the surface of the pattern P1 to change from hydrophobic tohydrophilic. Therefore, the pre-drying processing liquid is supplied tothe silicon wafer when the surface of the pattern P1 is hydrophilic.

As shown in FIG. 22, after the substrate W has started to rotate (stepS2 in FIG. 22), a first chemical liquid supplying step (step S3-1 inFIG. 22) is performed to supply hydrofluoric acid serving as an exampleof chemical liquid to the upper surface of the substrate W and therebyform a liquid film of hydrofluoric acid covering the entire uppersurface of the substrate W.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 34 moves the chemical liquid nozzle 31 from the standbyposition to the processing position. Thereafter, the chemical liquidvalve 33 is opened, so that the chemical liquid nozzle 31 starts todischarge the hydrofluoric acid. When a predetermined time has elapsedafter the chemical liquid valve 33 was opened, the chemical liquid valve33 is closed to thereby stop discharging the hydrofluoric acid.Thereafter, the nozzle moving unit 34 moves the chemical liquid nozzle31 to the standby position.

The hydrofluoric acid discharged from the chemical liquid nozzle 31collides with the upper surface of the substrate W that is rotating atthe liquid supplying speed and then, flows outwardly along the uppersurface of the substrate W due to centrifugal force. Thus, thehydrofluoric acid is supplied to the entire upper surface of thesubstrate W to thereby form the liquid film of hydrofluoric acidcovering the entire upper surface of the substrate W. While the chemicalliquid nozzle 31 is discharging the hydrofluoric acid, the nozzle movingunit 34 may move a liquid landing position so that the liquid landingposition of the hydrofluoric acid passes the center portion and theouter circumference portion of the upper surface of the substrate W oralternatively, may bring the liquid landing position to a standstill atthe center portion.

Next, a first rinse liquid supplying step (step S4-1 in FIG. 22) isperformed to supply pure water serving as an example of rinse liquid tothe upper surface of the substrate W and thereby wash away thehydrofluoric acid on the substrate W.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 38 moves the rinse liquid nozzle 35 from the standbyposition to the processing position. Thereafter, the rinse liquid valve37 is opened, so that the rinse liquid nozzle 35 starts to discharge arinse liquid. Before pure water starts to be discharged, the guardelevating/lowering unit 27 may vertically move at least one guard 24 inorder to switch the guard 24 that receives the liquid discharged fromthe substrate W. When a predetermined time has elapsed after the rinseliquid valve 37 is opened, the rinse liquid valve 37 is closed tothereby stop discharging the rinse liquid. Thereafter, the nozzle movingunit 38 moves the rinse liquid nozzle 35 to the standby position.

The pure water discharged from the rinse liquid nozzle 35 collides withthe upper surface of the substrate W that is rotating at the liquidsupplying speed, and then, flows outwardly along the upper surface ofthe substrate W due to centrifugal force. The hydrofluoric acid on thesubstrate W is replaced with the pure water discharged from the rinseliquid nozzle 35. This causes a liquid film of pure water covering theentire upper surface of the substrate W to be formed. While the rinseliquid nozzle 35 is discharging pure water, the nozzle moving unit 38may move a liquid landing position so that the liquid landing positionof the pure water passes the center portion and the outer circumferenceportion of the upper surface of the substrate W, or alternatively, maybring the liquid landing position to a standstill at the center portion.

Next, a second chemical liquid supplying step (step S3-2 in FIG. 22) isperformed to supply SC1 serving as an example of chemical liquid to theupper surface of the substrate W to thereby form a liquid film of SC1covering the entire upper surface of the substrate W.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 34B moves the second chemical liquid nozzle 31B from thestandby position to the processing position. Thereafter, the secondchemical liquid valve 33B is opened, so that the second chemical liquidnozzle 31B starts to discharge SC1. When a predetermined time haselapsed after the second chemical liquid valve 33B is opened, the secondchemical liquid valve 33B is closed to thereby stop discharging the SC1.Thereafter, the nozzle moving unit 34B moves the second chemical liquidnozzle 31B to the standby position.

The SC1 discharged from the second chemical liquid nozzle 31B collideswith the upper surface of the substrate W that is rotating at the liquidsupplying speed, and then, flows outwardly along the upper surface ofthe substrate W due to centrifugal force. The pure water on thesubstrate W is replaced with the SC1 discharged from the second chemicalliquid nozzle 31B. This causes a liquid film of SC1 covering the entireupper surface of the substrate W to be formed. While the second chemicalliquid nozzle 31B is discharging SC1, the nozzle moving unit 34B maymove a liquid landing position so that the liquid landing position ofthe SC1 passes the center portion and the outer circumference portion ofthe upper surface of the substrate W, or alternatively, may bring theliquid landing position to a standstill at the center portion.

Next, a second rinse liquid supplying step (step S4-2 in FIG. 22) isperformed to supply pure water serving as an example of rinse liquid tothe upper surface of the substrate W and thereby wash away the SC1 onthe substrate W.

Specifically, with the shielding member 51 located at the upper positionand at least one guard 24 located at the upper position, the nozzlemoving unit 38 moves the rinse liquid nozzle 35 from the standbyposition to the processing position. Thereafter, the rinse liquid valve37 is opened, so that the rinse liquid nozzle 35 starts to discharge therinse liquid. Before the pure water starts to be discharged, the guardelevating/lowering unit 27 may vertically move at least one guard 24 inorder to switch the guard 24 that receives the liquid discharged fromthe substrate W. When a predetermined time has elapsed after the rinseliquid valve 37 was opened, the rinse liquid valve 37 is closed tothereby stop discharging the rinse liquid. Thereafter, the nozzle movingunit 38 moves the rinse liquid nozzle 35 to the standby position.

The pure water discharged from the rinse liquid nozzle 35 collides withthe upper surface of the substrate W that is rotating at the liquidsupplying speed, and then, flows outwardly along the upper surface ofthe substrate W due to centrifugal force. The SC1 on the substrate W isreplaced with the pure water discharged from the rinse liquid nozzle 35.This causes a liquid film of pure water covering the entire uppersurface of the substrate W to be formed. While the rinse liquid nozzle35 is discharging the pure water, the nozzle moving unit 38 may move aliquid landing position so that the liquid landing position of the purewater passes the center portion and the outer circumference portion ofthe upper surface of the substrate W, or alternatively, may bring theliquid landing position to a standstill at the center portion.

In a similar manner as the example of processing the substrate Waccording to the first preferred embodiment shown in FIG. 5, after thesecond rinse liquid supplying step (step S4-2 in FIG. 22) is performed,the replacement liquid and the pre-drying processing liquid aresequentially supplied to the substrate W (step S5 to step S6 in FIG. 22)to sublimate the solidified body 101 (see FIG. 23E) on the front surfaceof the substrate W (step S7 to step S9 in FIG. 22). Thereafter, thesubstrate W is carried out of the chamber 4 (step S10 to step S11 inFIG. 22). Thus, the processed substrate W is carried out of the chamber4.

Next, description will be made for a possible phenomenon that may occuron the surface of the pattern P1 to which the pre-drying processingliquid is supplied.

FIG. 23A to FIG. 23F are a cross-sectional view of the substrate W fordescribing the phenomenon. FIG. 23A to FIG. 23E show tertiary butylalcohol as TBA. FIG. 23A to FIG. 23C show the hydrophilic group of thetertiary butyl alcohol molecule in a bold straight line and thehydrophobic group of the tertiary butyl alcohol molecule is shown by ablack circle.

As described above, in the example of processing the substrate Waccording to the second preferred embodiment, hydrofluoric acid and SC1are sequentially supplied to a silicon wafer corresponding to thesubstrate W. The surface of the pattern P1 changes to hydrophobic bysupplying the hydrofluoric acid. Thereafter, the surface of the patternP1 changes to hydrophilic by supplying the SC1. Therefore, thepre-drying processing liquid containing camphor, IPA, and tertiary butylalcohol is supplied to the silicon wafer when the surface of the patternP1 is hydrophilic.

The camphor can be regarded as hydrophobic, and the tertiary butylalcohol has amphiphilic molecules that contain both the hydrophilicgroup and the hydrophobic group. As shown in FIG. 23A, since the surfaceof the pattern P1 is hydrophilic, the hydrophilic group of the tertiarybutyl alcohol molecule is attracted to the surface of the pattern P1. Asshown in FIG. 23B, this allows the hydrophilic group of the tertiarybutyl alcohol molecule to be adsorbed to the surface of the pattern P1.Thus, a thin film of tertiary butyl alcohol is formed on a side surfacePs and an upper surface Pu of the pattern P1.

FIG. 23B shows an example in which a monomolecular film of tertiarybutyl alcohol is formed across the surface of the pattern P1. As shownin FIG. 23C, in the case of the example, the hydrophobic group of thecamphor molecule is adhered to the hydrophobic group of the tertiarybutyl alcohol molecule adsorbed to the surface of the pattern P1. When astacked film of tertiary butyl alcohol is formed across the surface ofthe pattern P1, the hydrophobic group of the camphor molecule is adheredto the hydrophobic group of the tertiary butyl alcohol molecule exposedon the surface layer of the stacked film. This allows the camphor to beheld on the surface of the pattern P1 through the thin film of tertiarybutyl alcohol.

As shown in FIG. 23C, the camphor molecule in the pre-drying processingliquid is adhered to the camphor molecule held on the thin film oftertiary butyl alcohol. The phenomenon causes a large number of camphormolecules to be held on the side surface Ps of the pattern P1 throughthe molecular layer of tertiary butyl alcohol. Thus, as shown in FIG.23D, a sufficient amount of camphor molecules enter in between patternsP1. FIG. 23D shows an example in which the thin film of tertiary butylalcohol is formed not only on the side surface Ps and the upper surfacePu of the pattern P1 but also on a bottom surface Pb of a recessedportion formed between two adjacent patterns P1.

The IPA corresponding to the solvent evaporates from the pre-dryingprocessing liquid with the thin film of tertiary butyl alcohol formedalong the surface of the pattern P1 and a plurality of camphor moleculesheld on the surface of the pattern P1 through the thin film of tertiarybutyl alcohol. As the IPA evaporates, the freezing point of thepre-drying processing liquid rises, and the concentrations of thecamphor and the tertiary butyl alcohol increase. As shown in FIG. 23E,this causes the solidified body 101 containing the camphor and thetertiary butyl alcohol to be formed on the front surface of thesubstrate W. Thereafter, as shown in FIG. 23F, the solidified body 101is vaporized to be thereby removed from the front surface of thesubstrate W.

According to the studies by the present inventors, it was confirmed thatthe collapse rate of the pattern P1 has been lowered as compared withusing a solution of camphor and IPA as the pre-drying processing liquidwhen the processing the substrate W according to the second preferredembodiment is performed using a plate-shaped silicon sample, on whichthe pattern P1 has been formed, in place of the substrate W, and using asolution of camphor, IPA, and tertiary butyl alcohol as the pre-dryingprocessing liquid. When the concentration of tertiary butyl alcohol(volume percent concentration) was changed within the range from 0.1 vol% to 10 vol %, no significant difference was found among the collapserates of the pattern P1. Therefore, adding even a small amount oftertiary butyl alcohol will lower the collapse rate of the pattern P1.The concentration of tertiary butyl alcohol may have a value within therange or may also be a value outside the range.

In addition to the effects according to the first preferred embodiment,the second preferred embodiment can obtain the following effects.Specifically, in the second preferred embodiment, the pre-dryingprocessing liquid containing the adsorbent substance is supplied to thefront surface of the substrate W, on which the pattern P1 has beenformed, in addition to the sublimable substance and the solvent.Thereafter, the solvent is evaporated from the pre-drying processingliquid. This allows the solidified body 101 containing the sublimablesubstance to be formed on the front surface of the substrate W.Thereafter, the solidified body 101 on the substrate W is changed to gaswithout passing through to a liquid. This causes the solidified body 101to be removed from the front surface of the substrate W. Therefore, thecollapse rate of the pattern P1 can be lowered as compared with theconventional drying method such as the spin dry.

The sublimable substance is a substance that contains the hydrophobicgroup in the molecule. The adsorbent substance is a substance thatcontains the hydrophobic group and the hydrophilic group in themolecule. The adsorbent substance is higher in hydrophilicity than thesublimable substance. Whether the surface of the pattern P1 ishydrophilic or hydrophobic, or alternatively even when the surface ofthe pattern P1 includes a hydrophilic portion and a hydrophobic portion,the adsorbent substance in the pre-drying processing liquid is adsorbedto the surface of the pattern P1.

Specifically, when the surface of the pattern P1 is hydrophilic, thehydrophilic group of the adsorbent substance in the pre-dryingprocessing liquid is adhered to the surface of the pattern P1, and thehydrophobic group of the sublimable substance in the pre-dryingprocessing liquid is adhered to the hydrophobic group of the adsorbentsubstance. This allows the sublimable substance to be held on thesurface of the pattern P1 through the adsorbent substance. When thesurface of the pattern P1 is hydrophobic, at least the hydrophobic groupof the sublimable substance is adhered to the surface of the pattern P1.Therefore, whether the surface of the pattern P1 is hydrophilic orhydrophobic, or alternatively even when the surface of the pattern P1includes a hydrophilic portion and a hydrophobic portion, the sublimablesubstance is held on the surface of the pattern P1 or in its vicinitybefore the solvent is evaporated.

When the sublimable substance is hydrophilic, and the surface of thepattern P1 is hydrophilic, the sublimable substance is attracted to thesurface of the pattern P1 due to electrical attractive force. Meanwhile,when the sublimable substance is hydrophobic, and the surface of thepattern P1 is hydrophilic, such attractive force is weak or neveroccurs, and thus the sublimable substance is unlikely to adhere to thesurface of the pattern P1. Furthermore, when the sublimable substance ishydrophobic, and the patterns P1 have very narrow spacings in additionto the surface of the pattern P1 being hydrophilic, it is thought that asufficient amount of sublimable substance may not enter between thepatterns P1. These phenomena also occur when the sublimable substance ishydrophilic, and the surface of the pattern P1 is hydrophobic.

When the solvent is evaporated while the sublimable substance is notfound on the surface of the pattern P1 or in its vicinity, the solventin contact with the surface of the pattern P1 may apply a collapsingforce to the pattern P1, causing the pattern P1 to be collapsed. Whenthe solvent is evaporated while a sufficient amount of sublimablesubstance is not found between the patterns P1, it is also thought thatspacings between the patterns P1 may not be filled with the solidifiedbody 101, thus causing the pattern P1 to be collapsed. If the sublimablesubstance is disposed on the surface of the pattern P1 or in itsvicinity before the solvent is evaporated, such collapse can be reduced.This makes it possible to lower the collapse rate of the pattern P1.

In the second preferred embodiment, not only the sublimable substancebut also the adsorbent substance has sublimability. The adsorbentsubstance changes from solid to gas without passing through to a liquidat normal temperature or at normal pressure. When at least a portion ofthe surface of the pattern P1 is hydrophilic, the solvent evaporateswith the adsorbent substance in the pre-drying processing liquidadsorbed to the surface of the pattern P1. The adsorbent substancechanges from liquid to solid on the surface of the pattern P1. Thisallows the solidified body 101 containing the adsorbent substance andthe sublimable substance to be formed. Thereafter, the solid of theadsorbent substance changes to gas without passing through to a liquidon the surface of the pattern P1. Therefore, the collapsing force can belowered as compared with the case where the liquid is vaporized on thesurface of the pattern P1.

In the second preferred embodiment, the pre-drying processing liquidhaving the adsorbent substance of a lower concentration is supplied tothe front surface of the substrate W. When at least a portion of thesurface of the pattern P1 is hydrophilic, the hydrophilic group of theadsorbent substance is adhered to the surface of the pattern P1, so thatthe monomolecular film of the adsorbent substance is formed along thesurface of the pattern P1. At a high concentration of the adsorbentsubstance, a plurality of monomolecular films are stacked in layers, sothat the stacked film of the adsorbent substance is formed along thesurface of the pattern P1. In the case, the sublimable substance is heldon the surface of the pattern P1 through the stacked film of theadsorbent substance. A thick stacked film of the adsorbent substancecauses the sublimable substance entering between patterns P1 to bereduced. Therefore, by lowering the concentration of the adsorbentsubstance, a greater amount of the sublimable substance can enterbetween the patterns P1.

In the second preferred embodiment, the pre-drying processing liquidcontaining the sublimable substance that is higher in hydrophobicitythan the adsorbent substance is supplied to the front surface of thesubstrate W. Since any of the sublimable substance and the adsorbentsubstance contains the hydrophobic group, when at least a portion of thesurface of the pattern P1 is hydrophobic, both the sublimable substanceand the adsorbent substance can be adhered to the surface of the patternP1. However, since the affinity between the sublimable substance and thepattern P1 is higher than the affinity between the adsorbent substanceand the pattern P1, a greater amount of the sublimable substance ascompared with the adsorbent substance is adhered to the surface of thepattern P1. This allows more sublimable substance to be adhered to thesurface of the pattern P1.

Other Preferred Embodiments

The present invention is not restricted to the contents of the abovedescribed preferred embodiments and various modifications are possible.

For example, to change the thickness T1 of the solidified body 101, acondition other than the concentration of the pre-drying processingliquid may be changed. For example, in addition to or in place of theconcentration of the pre-drying processing liquid, the temperature ofthe pre-drying processing liquid may be changed.

The pattern P1 is not limited to a single-layer structure, but may havea layered structure. At least a portion of the pattern P1 may be formedof a material other than silicon. For example, at least a portion of thepattern P1 may be formed of metal.

In an example of processing the substrate W according to First and thesecond preferred embodiments, to maintain the pre-drying processingliquid on the substrate W in a liquid state, a temperature holding stepmay be performed to maintain the pre-drying processing liquid on thesubstrate W at a liquid holding temperature that is higher than thefreezing point of the pre-drying processing liquid and lower than theboiling point of the pre-drying processing liquid.

When the rinse liquid such as pure water on the substrate W can bereplaced with the pre-drying processing liquid, the pre-dryingprocessing liquid supplying step may be performed without performing thereplacement liquid supplying step to replace the rinse liquid on thesubstrate W with the replacement liquid.

In an example of processing the substrate W according to the secondpreferred embodiment, the surface of the pattern P1 may be hydrophilicfrom the beginning, that is, before being carried into the substrateprocessing apparatus 1. In the case, the second chemical liquidsupplying step (step S3-2 in FIG. 22) and the second rinse liquidsupplying step (step S4-2 in FIG. 22) may be eliminated. Furthermore,the chemical liquid supplied to the substrate W in the first chemicalliquid supplying step (step S3-1 in FIG. 22) may be a chemical liquidother than hydrofluoric acid.

In an example of processing the substrate W according to the secondpreferred embodiment, when the pre-drying processing liquid is suppliedto the front surface of the substrate W, the surface of the pattern P1may be hydrophobic. In the case, the surface of the pattern P1 may behydrophobic from the beginning or may be changed to hydrophobic whilethe substrate W is being processed.

In the second preferred embodiment, if the initial concentration of thesublimable substance (the concentration of the sublimable substance inthe pre-drying processing liquid before being supplied to the substrateW) is not changed, one of the first tank 87A and the second tank 87Bshown in FIG. 3 may be eliminated.

In the second preferred embodiment, the adsorbent substance may be mixedwith a solution of the sublimable substance and the solvent at aposition outside the first tank 87A and the second tank 87B. In thecase, the adsorbent substance may be mixed before the solution of thesublimable substance and the solvent is discharged from the pre-dryingprocessing liquid nozzle 39, or may be mixed after the solution of thesublimable substance and the solvent is discharged from the pre-dryingprocessing liquid nozzle 39. In the latter case, the adsorbent substancemay be mixed with the solution of the sublimable substance and thesolvent in a space between the pre-drying processing liquid nozzle 39and the substrate W, or may be mixed with the solution of the sublimablesubstance and the solvent on the upper surface of the substrate W.

The shielding member 51 may include a cylindrical portion that extendsdownwardly from the outer circumferential portion of the disc portion 52in addition to the disc portion 52. In the case, when the shieldingmember 51 is disposed at the lower position, the substrate W held on thespin chuck 10 is surrounded by the cylindrical portion.

The shielding member 51 may rotate around the rotation axis A1 togetherwith the spin chuck 10. For example, the shielding member 51 may beplaced on the spin base 12 so as not to contact the substrate W. In thecase, since the shielding member 51 is coupled to the spin base 12, theshielding member 51 rotates at the same speed in the same direction asthat of the spin base 12.

The shielding member 51 may be eliminated. However, when a liquid suchas pure water is supplied to the lower surface of the substrate W, theshielding member 51 is preferably provided. This is because theshielding member 5 l can interrupt droplets that run across the outercircumferential surface of the substrate W to go around from the lowersurface of the substrate W to the upper surface of the substrate W orthose droplets that bounce inwardly from the processing cup 21, thusreducing a liquid that would be otherwise mixed into the pre-dryingprocessing liquid on the substrate W.

The substrate processing apparatus 1 is not restricted to an apparatusfor processing a disc-shaped substrate W, and may be an apparatus forprocessing a polygonal substrate W.

The substrate processing apparatus 1 is not restricted to a singlesubstrate processing type apparatus, and may be a batch type apparatusthat processes a plurality of substrates in a batch.

Two or more arrangements among all the arrangements described above maybe combined. Two or more steps among all the steps described above maybe combined.

The pre-drying processing liquid nozzle 39 is an example of thepre-drying processing liquid supplying unit. The central nozzle 55 andthe spin motor 14 are an example of a solidified body forming unit. Thecentral nozzle 55 and the spin motor 14 are an example of a sublimatingunit.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A substrate processing method comprising: apre-drying processing liquid supplying step of supplying a front surfaceof a substrate, on which a pattern has been formed, with a pre-dryingprocessing liquid containing a sublimable substance that changes to gaswithout passing through to a liquid and a solvent in which thesublimable substance dissolves; a solidified body forming step offorming a solidified body containing the sublimable substance on thefront surface of the substrate by evaporating the solvent from thepre-drying processing liquid on the front surface of the substrate; anda sublimating step of removing the solidified body from the frontsurface of the substrate by sublimating the solidified body, wherein avalue acquired by multiplying a ratio of a thickness of the solidifiedbody to a height of the pattern by 100 is greater than 76 and less than219, wherein the pre-drying processing liquid supplied to the frontsurface of the substrate in the pre-drying processing liquid supplyingstep is a solution that contains the sublimable substance containing ahydrophobic group, the solvent, and an adsorbent substance that containsa hydrophobic group and a hydrophilic group and is higher inhydrophilicity than the sublimable substance.
 2. The substrateprocessing method according to claim 1, wherein the adsorbent substanceis a substance having sublimability.
 3. The substrate processing methodaccording to claim 1, wherein a concentration of the adsorbent substancein the pre-drying processing liquid is lower than the concentration ofthe solvent in the pre-drying processing liquid.
 4. The substrateprocessing method according to claim 1, wherein the sublimable substanceis higher in hydrophobicity than the adsorbent substance.